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Usage
1 - Prerequisites
Prepare the SAP BTP global account and provider subaccount
CAP-based applications make use of various SAP BTP services that are created in a provider subaccount. So, before you can deploy the application, create a global account and assign the required services that will be used. To do so, use SAP BTP Control Center. Once done, create a provider subaccount, where the required service instances can be created.
Create service instances and bindings
A multi-tenant CAP-based application consumes the following SAP BTP services. While creating these service instances, some of the parameters supplied require special attention. Service keys (bindings) are then created to generate access credentials, which in turn should be provided as Kubernetes Secrets in the namespace where the application is being deployed.
Other services (not listed here) may also be used depending on the requirement (for example, SAP HTML5 Application Repository service for SAP BTP, Business Logging, and so on).
Note: If some SAP BTP services are not available on Kubernetes, enable Cloud Foundry for the provider subaccount to create certain services. In such cases you may use the cf-service-operator for managing the service instances and service bindings directly from within the Kubernetes cluster. Based on the service bindings, it automatically generates the secrets containing the service access credentials.
SAP Authorization and Trust Management Service
The parameter oauth2-configuration.redirect-uris
must include the domain used by the application. For instance, if the application is hosted in a “Gardener” managed cluster, the entry may have the form https://*<application-specific-prefix>.<cluster-id>.<gardener-project-id>.shoot.url.k8s.example.com/**
.
Scope required to make asynchronous tenant subscription operations need to be included. Additionally, check the CAP Multitenancy documentation for additional scopes which are required.
parameters:
authorities:
- $XSAPPNAME.mtcallback
- $XSAPPNAME.mtdeployment
oauth2-configuration:
redirect-uris:
- https://*my-cap-app.cluster-x.my-project.shoot.url.k8s.example.com/**
role-collections:
...
role-templates:
...
scopes:
- description: UAA
name: uaa.user
- description: With this scope set, the callbacks for tenant onboarding, offboarding, and getDependencies can be called
grant-as-authority-to-apps:
- $XSAPPNAME(application,sap-provisioning,tenant-onboarding)
name: $XSAPPNAME.Callback
- description: Async callback to update the saas-registry (provisioning succeeded/failed)
name: $XSAPPNAME.subscription.write
- description: Deploy applications
name: $XSAPPNAME.mtdeployment
- description: Subscribe to applications
grant-as-authority-to-apps:
- $XSAPPNAME(application,sap-provisioning,tenant-onboarding)
name: $XSAPPNAME.mtcallback
...
When using mulitple SAP Authorization and Trust Management Service instances in the app (for example, one for the application
and other apiaccess
). The primary instance can be set using the annotation: “sme.sap.com/primary-xsuaa” with the value being the name
of the service instance, as shown below:
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplication
metadata:
annotations:
"sme.sap.com/primary-xsuaa": "my-cap-app-uaa" # This let's the CAP Operator determine/use the right UAA instance for the application.
name: test-cap-01
...
spec:
btp:
services:
- class: xsuaa
name: my-cap-app-uaa-api
secret: my-cap-app-uaa-api-bind-cf
- class: xsuaa
name: my-cap-app-uaa
secret: my-cap-app-uaa-bind-cf
- class: saas-registry
name: my-cap-app-saas-registry
secret: my-cap-app-saas-bind-cf
...
btpAppName: my-cap-app
...
SAP Software-as-a-Service Provisioning service
When creating an instance of the SaaS Provisioning service, use asynchronous tenant subscription callbacks in the configuration. See Register Your Multi-Tenant Application/Service in SaaS Provisioning for more details.
parameters:
appName: <short-application-name>
appUrls:
callbackTimeoutMillis: 300000 # <-- used to fail subscription process when no response is received
getDependencies: https://<provider-subaccount-subdomain>.<cap-app-name>.cluster-x.my-project.shoot.url.k8s.example.com/callback/v1.0/dependencies # <-- handled by the application
onSubscription: https://<cap-operator-subscription-server-domain>/provision/tenants/{tenantId} # <-- the /provision route is forwarded directly to CAP Operator (Subscription Server) and must be specified as such
onSubscriptionAsync: true
onUnSubscriptionAsync: true
SAP HANA Cloud
An SAP HANA Cloud instance (preferably shared and accessible from the provider subaccount) is required. The Instance ID of the database must be noted for usage in relevant workloads. SAP HANA Schemas & HDI Containers service must also be entitled for the provider subaccount.
SAP Service Manager service
The SAP Service Manager service allows CAP to retrieve schema-(tenant-)specific credentials to connect to the SAP HANA Cloud database.
2 - Deploying a CAP Application
Just by defining two resources provided by CAP Operator, namely capapplications.sme.sap.com
and capapplicationversions.sme.sap.com
, it’s possible to deploy a multi-tenant CAP application and start using it. These resources are namespaced and so the CAP Operator will create all related resources (deployments, gateways, jobs etc.) within the same namespace.
The object, CAPApplication
, describes the high-level attributes of an application such as the SAP BTP account where it is hosted, the consumed SAP BTP services, domains where the application routes will be made available etc. See API Reference.
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplication
metadata:
name: cap-app-01
namespace: cap-app-01
spec:
btpAppName: cap-app-01 # <-- short name (similar to SAP BTP XSAPPNAME)
btp:
services:
- class: xsuaa # <-- SAP BTP service technical name
name: app-uaa # <-- name of the service instance
secret: cap-app-01-uaa-bind-cf # <-- secret containing the credentials to access the service existing in the same namespace
- class: saas-registry
name: app-saas-registry
secret: cap-app-01-saas-bind-cf
- class: service-manager
name: app-service-manager
secret: cap-app-01-svc-man-bind-cf
- class: destination
name: app-destination
secret: cap-app-01-dest-bind-cf
- class: html5-apps-repo
name: app-html5-repo-host
secret: cap-app-01-html5-repo-bind-cf
- class: html5-apps-repo
name: app-html5-repo-runtime
secret: cap-app-01-html5-rt-bind-cf
- class: portal
name: app-portal
secret: cap-app-01-portal-bind-cf
domains:
istioIngressGatewayLabels: # <-- labels used to identify the Istio ingress gateway (the values provided here are the default values)
- name: app
value: istio-ingressgateway
- name: istio
value: ingressgateway
primary: "cap-app-01.cluster.shoot.url.k8s.example.com" # <-- primary domain where the application is exposed. Each tenant will have access to a subdomain of this domain. Ensure that this is at most 62 chars long.
secondary:
- "alt.shoot.example.com"
globalAccountId: global-account-id
provider:
subDomain: cap-app-01-provider
tenantId: e55d7b5-279-48be-a7b0-aa2bae55d7b5
The object, CAPApplicationVersion
, describes the different components of an application version including the container images to be used and the services consumed by each component. See API Reference.
The CAPApplicationVersion
must be created in the same namespace as the CAPApplication
and refers to it.
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
name: cav-cap-app-01-1
namespace: cap-app-01
spec:
capApplicationInstance: cap-app-01 # <-- reference to CAPApplication in the same namespace
version: "1" # <-- semantic version
registrySecrets:
- regcred
workloads:
- name: cap-backend
consumedBTPServices: # <-- these are services used by the application server (already defines as part of CAPApplication resource). Corresponding credential secrets will be mounted onto the component pods as volumes.
- app-uaa
- app-service-manager
- app-saas-registry
deploymentDefinition:
type: CAP # <-- indicates the CAP application server
image: app.some.repo.example.com/srv/server:0.0.1
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
- name: app-router
consumedBTPServices:
- app-uaa
- app-destination
- app-saas-registry
- app-html5-repo-runtime
- app-portal
deploymentDefinition:
type: Router
image: app.some.repo.example.com/approuter/approuter:0.0.1
env:
- name: PORT
value: 4000
- name: TENANT_HOST_PATTERN
value: "^(.*).(cap-app-01.cluster.shoot.canary.k8s-hana.ondemand.co|alt.shoot.example.com)"
- name: service-content
consumedBTPServices:
- app-uaa
- app-html5-repo-host
- app-portal
jobDefinition:
type: Content
image: app.some.repo.example.com/approuter/content:0.0.1
backoffLimit: 1
NOTE: The example above is a minimal
CAPApplicationVersion
that can be deployed. For a more supported configuration and their explanations, see here.
The controller component of CAP Operator reacts to these objects and creates further resources, which constitute a running application:
- Deployment (and service) for the application server with credentials (from secrets) to access SAP BTP services injected as
VCAP_SERVICES
environment variable - Deployment (and service) for the approuter with destination mapping to the application server and subscription server (for the tenant provisioning route)
- Job for the version content deployer
- TLS certificates for the domains provided using either “Gardener” cert-management or cert-manager.io cert-manager
- Istio gateway resource for the application domains
The content deployer is used to deploy content or configuration to SAP BTP services, before using them.
Once these resources are available, the CAPApplicationVersion
status changes to Ready
. The controller proceeds to automatically create an object of type CAPTenant
, which corresponds to the tenant of the provider subaccount. Please see tenant subscription for details on how the CAPTenant
resource is reconciled.
The
CAPApplicationVersion
resource is meant to be immutable - it’s spec should not be modified once it is deployed. This is also prevented by our web-hooks which we recommend to always keep active (default).
3 - Tenant Subscription
From the perspective of CAP Operator, a valid tenant for an application is represented by the resource CAPTenant
. It refers to the CAPApplication
it belongs to and specifies the details of the SAP BTP subaccount representing the tenant.
apiVersion: sme.sap.com/v1alpha1
kind: CAPTenant
metadata:
name: cap-app-01-provider
namespace: cap-app-01
spec:
capApplicationInstance: cap-app-01 # <-- reference to the CAPApplication
subDomain: app-provider
tenantId: aa2bae55d7b5-1279-456564-a7b0-aa2bae55d7b5
version: "1.0.0" # <-- expected version of the application
versionUpgradeStrategy: always # <-- always / never
Tenant Provisioning
The process of tenant provisioning starts when a consumer subaccount subscribes to the application, either via the SAP BTP cockpit or using the APIs provided by the SaaS provisioning service. This, in turn, initiates the asynchronous callback from the SaaS provisioning service instance into the cluster, and the request is handled by the subscription server. The subscription server validates the request and creates an instance of CAPTenant
for the identified CAPApplication
.
Warning
An instance ofCAPTenant
must not be created or deleted manually within the cluster. A new instance has to be created by the subscription server after receiving a provisioning call from SaaS provisioning service.The controller, observing the new CAPTenant
, will initiate the provisioning process by creating the resource CAPTenantOperation
, which represents the provisioning operation.
apiVersion: sme.sap.com/v1alpha1
kind: CAPTenantOperation
metadata:
name: cap-app-01-provider-sgz8b
namespace: cap-app-01
spec:
capApplicationVersionInstance: cav-cap-app-01-1 # <-- latest CAPApplicationVersion in Ready state
subDomain: app-provider
tenantId: aa2bae55d7b5-1279-456564-a7b0-aa2bae55d7b5
operation: provisioning # <-- valid values are provisioning, deprovisioning and upgrade
steps:
- name: cap-backend # <-- derived from workload of type CAP (when workload of type TenantOperation is not specified)
type: TenantOperation
The CAPTenantOperation
is further reconciled to create Kubernetes jobs (steps), which are derived from the latest CAPApplicationVersion
, which is in Ready
state. The steps comprise of a TenantOperation
job and optional CustomTenantOperation
steps. The TenantOperation
step uses built in CLI-based tenant operations from @sap/cds-mtxs
to execute tenant provisioning.
The CAPTenant
reaches a Ready
state, only after
- a successful completion of all
CAPTenantOperation
steps. - the creation of Istio
VirtualService
, which allows HTTP requests on the tenant subdomain to reach the application.
Tenant Deprovisioning
Similar to the tenant provisioning process, when a tenant unsubscribes from the application, the request is received by the subscription server. It validates the existence and status of the CAPTenant
and submits a request for deletion to the Kubernetes API server.
The controller identifies that the CAPTenant
has to be deleted, but withholds deletion until it can create and watch for a successful completion of a CAPTenantOperation
of type deprovisioning. The CAPTenantOperation
creates the corresponding jobs (steps), which execute the tenant deprovisioning.
4 - Application Upgrade
An important lifecycle aspect of operating multi-tenant CAP applications is the tenant upgrade process. With CAP Operator, these tenant upgrades can be fully automated by providing a new instance of the capapplicationversions.sme.sap.com
custom resource.
As you’ve already seen during the initial deployment, the CAPApplicationVersion
resource describes the different components (workloads) of an application version that includes the container image to be used and the services consumed by each component.
To upgrade the application, provide a new CAPApplicationVersion
with the relevant image
for each component and use a newer (higher) semantic version in the version
field. See API Reference.
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
name: cav-cap-app-01-2
namespace: cap-app-01
spec:
capApplicationInstance: cap-cap-app-01 # <-- reference to CAPApplication in the same namespace
version: "2.0.1" # <-- semantic version
registrySecrets:
- regcred
workloads:
- name: cap-backend
consumedBTPServices:
- app-uaa
- app-service-manager
- app-saas-registry
deploymentDefinition:
type: CAP # <-- indicates the CAP application server
image: app.some.repo.example.com/srv/server:0.0.2
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
- name: app-router
consumedBTPServices:
- app-uaa
- app-destination
- app-saas-registry
- app-html5-repo-runtime
- app-portal
deploymentDefinition:
type: Router
image: app.some.repo.example.com/approuter/approuter:0.0.2
env:
- name: PORT
value: 4000
- name: TENANT_HOST_PATTERN
value: "^(.*).(cap-app-01.cluster.shoot.canary.k8s-hana.ondemand.co|alt.shoot.example.com)"
- name: service-content
consumedBTPServices:
- app-uaa
- app-html5-repo-host
- app-portal
jobDefinition:
type: Content
image: app.some.repo.example.com/approuter/content:0.0.2
backoffLimit: 1
- name: tenant-operation
consumedBTPServices:
- app-uaa
- app-service-manager
- app-saas-registry
jobDefinition:
type: TenantOperation
image: app.some.repo.example.com/approuter/content:0.0.2
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
- name: notify-upgrade
consumedBTPServices: []
jobDefinition:
type: CustomTenantOperation
image: app.some.repo.example.com/approuter/content:0.0.2
command: ["npm", "run", "notify:upgrade"]
backoffLimit: 1
env:
- name: TARGET_DL
value: group_xyz@sap.com
tenantOperations:
upgrade:
- workloadName: tenant-operation
- workloadName: notify-upgrade
continueOnFailure: true
Note that in this version (compared to version “1” used for the initial deployment), new workloads of type TenantOperation
and CustomTenantOperation
have been added.
The controller component of CAP Operator reacts to the new CAPApplicationVersion
resource and triggers another deployment for the application server, router and triggers the content deployment job. Once the new CAPApplicationVersion
is Ready
, the controller proceeds to automatically upgrade all relevant tenants i.e. by updating the version
attribute on the CAPTenant
resources.
The reconciliation of a CAPTenant
changes its state to Upgrading
and creates the CAPTenantOperation
resource of type upgrade.
apiVersion: sme.sap.com/v1alpha1
kind: CAPTenantOperation
metadata:
name: cap-app-01-provider-fgdfg
namespace: cap-app-01
spec:
capApplicationVersionInstance: cav-cap-app-01-2
subDomain: cap-provider
tenantId: aa2bae55d7b5-1279-456564-a7b0-aa2bae55d7b5
operation: upgrade # possible values are provisioning / upgrade / deprovisioning
steps:
- name: "tenant-operation"
type: TenantOperation
- name: "notify-upgrade"
type: CustomTenantOperation
continueOnFailure: true # <-- can be set for workloads of type CustomTenantOperation to indicate that the success of this job is optional for the completion of the overall operation
The CAPTenantOperation
creates jobs for each of the steps involved and executes them sequentially until all the jobs are finished or one of them fails. The CAPTenant
is notified about the result and updates its state accordingly.
A successful completion of the CAPTenantOperation
will cause the VirtualService
managed by the CAPTenant
to be modified to route HTTP traffic to the deployments of the newer CAPApplicationVersion
. Once all tenants have been upgraded, the outdated CAPApplicationVersion
can be deleted.
5 - Version Monitoring
In a continuous delivery environment where newer applications versions may be deployed frequently, monitoring and cleaning up older unused versions becomes important to conserve cluster resources (compute, memory, storage etc.) and operate a clutter free system. The CAP Operator now provides application developers and operations teams to define how an application version can be monitored for usage.
Integration with Prometheus
Prometheus is the industry standard for monitoring application metrics and provides a wide variety of tools for managing and reporting metrics data. The CAP Operator (controller) can be connected to a Prometheus server by setting the PROMETHEUS_ADDRESS
environment variable on the controller (see Configuration). The controller is then able to query application related metrics based on the workload specification of CAPApplicationVersions
. If no Prometheus address is supplied, the version monitoring function of the controller is not started.
Configure CAPApplication
To avoid incompatible changes, version cleanup monitoring must be enabled for CAP application using the annotation sme.sap.com/enable-cleanup-monitoring
. The annotation can have the following values which affects the version cleanup behavior:
Value | Behavior |
---|---|
dry-run | When a CAPApplicationVersion is evaluated to be eligible for cleanup, an event of type ReadyForDeletion is emitted without performing the actual deletion of the version. |
true | When a CAPApplicationVersion is evaluated to be eligible for cleanup, the version is deleted and an event of type ReadyForDeletion is emitted. |
Configure CAPApplicationVersion
For each workload of type deployment in a CAPApplicationVersion
, it is possible to define:
- Deletion rules: A criteria based on metrics which when satisfied signifies that the workload can be removed
- Scrape configuration: Configuration which defines how metrics are scraped from the workload service.
Deletion Rules (Variant 1) based on Metric Type
The following example shows how a workload, named backend
, is configured with deletion rules based on multiple metrics.
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
namespace: demo
name: cav-demo-app-1
spec:
workloads:
- name: backend
deploymentDefinition:
monitoring:
deletionRules:
metrics:
- calculationPeriod: 90m
name: current_sessions
thresholdValue: "0"
type: Gauge
- calculationPeriod: 2h
name: total_http_requests
thresholdValue: "0.00005"
type: Counter
This informs the CAP Operator that workload backend
is supplying two metrics which can be monitored for usage.
Metric
current_sessions
is of typeGauge
which indicates that it is an absolute value at any point of time. When evaluating this metric, the CAP operator queries Prometheus with a PromQL expression which calculates the average value of this metric over a specified calculation period. The average value from each time series is then added together to get the evaluated value. The evaluated value is then compared against the specified threshold value to determine usage (or eligibility for cleanup).Evaluation steps for metric type Gauge
Execute PromQL expression sum(avg_over_time(current_sessions{job="cav-demo-app-1-backend-svc",namespace="demo"}[90m]))
to get the evaluated valueCheck whether evaluated value <= 0 (the specified thresholdValue
)Similarly, metric
total_http_requests
is of typeCounter
which indicates that it is a cumulative value which can increment. When evaluating this metric, the CAP operator queries Prometheus with a PromQL expression which calculates the rate (of increase) of this metric over a specified calculation period. The rate of increase from each time series is then added together to get the evaluated value. The evaluated value is then compared against the specified threshold value to determine usage (or eligibility for cleanup).Evaluation steps for metric type Counter
Execute PromQL expression sum(rate(total_http_requests{job="cav-demo-app-1-backend-svc",namespace="demo"}[2h]))
to get the evaluated valueCheck whether evaluated value <= 0.00005 (the specified thresholdValue
)
Prometheus Metrics Data
- Prometheus stores metric data as multiple time series by label set. The number of time series created from a single metric depends on the possible combination of labels. The label
job
represents the source of the metric and (within Kubernetes) is the service representing the workload. - CAP Operator does not support Prometheus metric types other than
Gauge
andCounter
. Lean more about metric types here.
All specified metrics of a workload must satisfy the evaluation criteria for the workload to be eligible for cleanup.
Deletion Rules (Variant 2) as PromQL expression
Another way to specify the deletion criteria for a workload is by providing a PromQL expression which results a boolean scalar.
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
namespace: demo
name: cav-demo-app-1
spec:
workloads:
- name: backend
deploymentDefinition:
monitoring:
deletionRules:
expression: scalar(sum(avg_over_time(current_sessions{job="cav-demo-app-1-backend-svc",namespace="demo"}[2h]))) <= bool 5
The supplied PromQL expression is executed as a Prometheus query by the CAP Operator. The expected result is a scalar boolean (0
or 1
). Users may use comparison binary operators with the bool
modifier to achieve the expected result. If the evaluation result is true (1
), the workload is eligible for removal.
This variant can be useful when:
- the predefined evaluation based on metric types is not enough for determining usage of a workload.
- custom metrics scraping configurations are employed where the
job
label in the collected time series data does not mach the name of the (Kubernetes) Service created for the workload.
Scrape Configuration
Prometheus Operator is a popular Kubernetes operator for managing Prometheus and related monitoring components. A common way to setup scrape targets for a Prometheus instance is by creating the ServiceMonitor
resource which specifies which Services
(and ports) that should be scraped for collecting application metrics.
Prerequisite
ThescrapeConfig
feature of a workload is usable only when the ServiceMonitor
Custom Resource is available on the Kubernetes cluster.The CAP Operator provides an easy way to create Service Monitors
which target the Services
created for version workloads. The following sample shows how to configure this.
kind: CAPApplicationVersion
metadata:
namespace: demo
name: cav-demo-app-1
spec:
workloads:
- name: backend
deploymentDefinition:
ports:
- appProtocol: http
name: metrics-port
networkPolicy: Cluster
port: 9000
monitoring:
deletionRules:
expression: scalar(sum(avg_over_time(current_sessions{job="cav-demo-app-1-backend-svc",namespace="demo"}[2h]))) <= bool 5
scrapeConfig:
interval: 15s
path: /metrics
port: metrics-port
With this configuration the CAP Operator will create a ServiceMonitor
which targets the workload Service
. The scrapeConfig.port
should match the name of one of the ports specified on the workload.
Use Case
The workloadscrapeConfig
aims to support a minimal configuration, creating a ServiceMonitor
which supports the most common use case (i.e. scraping the workload service via. a defined workload port). To use complex configurations in ServiceMonitors
, they should be created separately. If the scrapeConfig
of a version workload is empty, the CAP Operator will not attempt to create the related ServiceMonitor
.Evaluating CAPApplicationVersions
for cleanup
At specified intervals (dictated by controller environment variable METRICS_EVAL_INTERVAL
), the CAP Operator selects versions which are candidates for evaluation.
- Only versions for
CAPApplications
where annotationsme.sap.com/enable-cleanup-monitoring
is set are considered. - All versions (
spec.version
) higher than the highest version withReady
status are not considered for evaluation. If there is no version with statusReady
, no versions are considered. - All versions linked to a
CAPTenant
are excluded from evaluation. This includes versions where the following fields of aCAPTenant
point to the version:status.currentCAPApplicationVersionInstance
- current version of the tenant.spec.version
- the version to which a tenant is upgrading.
Workloads from the identified versions are then evaluated based on the defined deletionRules
. Workloads without deletionRules
are automatically eligible for cleanup. All workloads (with type deployment) of a version must satisfy the evaluation criteria for the version to be deleted.
6 - Operator Metrics
Overview
The CAP Operator includes built-in Prometheus metrics that enable users to effectively monitor and analyze the operator’s performance. These metrics can provide insights into resource usage, potential issues, and overall operator health. The metrics are accessible at the /metrics
endpoint on port 9090
of both the Controller and the Subscription Server.
Controller Metrics
The Controller emits several types of metrics, including:
- Standard Go Metrics: These metrics are provided by the Prometheus Go client and include runtime statistics.
- Workqueue Metrics: These metrics are relevant to the resources being reconciled and are based on the MetricsProvider.
- Specific metrics: mentioned below.
Specific Metrics
- Reconcile Errors –
cap_op_reconcile_errors
, e.g.:
cap_op_reconcile_errors{kind="CAPApplication",name="my-app",namespace="app"} 11
- Type: Counter
- Description: This metric tracks the total number of resources that failed to reconcile for each resource kind, such as
CAPApplication
.
- Tenant Operations –
cap_op_tenant_operations
, e.g.
cap_op_tenant_operations{app="<hash>",operation="provisioning"} 83
- Type: Counter
- Description: This metric provides insights into overall tenant operations being performed.
Detailed Operational Metrics
To gain deeper insights, you can enable more granular metrics by setting the environment variable DETAILED_OPERATIONAL_METRICS
to "true"
.
- Failed Tenant Operations –
cap_op_tenant_operation_failures
, e.g.:
cap_op_tenant_operation_failures{app="<hash>",operation="upgrade",tenant_id="<guid>",namespace="app",name="my-app-tenant-op-xxyyz"} 2
- Type: Counter
- Description: This metric reveals the number of failed tenant operations, categorized by application, tenant ID, and specific operation details.
- Last Tenant Operation Duration –
cap_op_last_tenant_operation_duration_seconds
, e.g.:
cap_op_last_tenant_operation_duration_seconds{app="<hash>",tenant_id="<guid>"} 17
- Type: Gauge
- Description: This metric measures the duration (in seconds) of the last tenant operation for a specified application and tenant.
Subscription Server Metrics
The Subscription Server emits the following metrics:
- Standard Go Metrics: These metrics are provided by the Prometheus Go client and include runtime statistics.
- Specific metrics: mentioned below.
Specific Metrics
- Subscription Requests Total –
cap_op_subscription_requests_total
, e.g.:
cap_op_subscription_requests_total{code="202",method="POST"} 2024
- Type: Counter
- Description: This metric tracks the total number of subscription requests that were processed, categorized by HTTP method and response code.
- Inflight Subscription Requests –
cap_op_subscription_requests_inflight
, e.g.:
cap_op_subscription_requests_inflight{} 4
- Type: Gauge
- Description: This metric indicates the number of subscription requests currently being processed by the server.
Conclusion
The CAP Operator provides a rich set of metrics to facilitate monitoring and operational insights. By effectively leveraging these metrics, you can monitor and ensure the reliability and performance of your applications. For further details, consider exploring the Prometheus documentation and integrating these metrics into your monitoring systems.
7 - Resources
7.1 - CAPApplication
CAPApplication
resourceHere’s an example of a fully configured CAPApplication
:
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplication
metadata:
name: cap-app
namespace: cap-ns
spec:
btp:
services:
- class: xsuaa
name: cap-uaa
secret: cap-uaa-bind
- class: saas-registry
name: cap-saas-reg
secret: cap-saas-reg-bind
- class: service-manager
name: cap-service-manager
secret: cap-svc-man-bind
- class: destination
name: cap-destination
secret: cap-bem-02-dest-bind
- class: html5-apps-repo
name: cap-html5-repo-host
secret: cap-html5-repo-bind
- class: html5-apps-repo
name: cap-html5-repo-runtime
secret: cap-html5-rt-bind
- class: portal
name: cap-portal
secret: cap-portal-bind
- class: business-logging
name: cap-business-logging
secret: cap-business-logging-bind
btpAppName: cap-app
domains:
istioIngressGatewayLabels: # <-- labels used to identify Load Balancer service used by Istio
- name: app
value: istio-ingressgateway
- name: istio
value: ingressgateway
primary: cap-app.cluster.project.shoot.url.k8s.example.com
secondary:
- alt-cap.cluster.project.shoot.url.k8s.example.com
globalAccountId: 2dddd48d-b45f-45a5-b861-a80872a0c8a8
provider: # <-- provider tenant details
subDomain: cap-app-provider
tenantId: 7a49218f-c750-4e1f-a248-7f1cefa13010
The overall list of SAP BTP service instances and respective Secrets (credentials) required by the application is specified as an array in btp.services
. These service instances are assumed to exist in the provider subaccount. Operators such as cf-service-operator or sap-btp-service-operator can be used to declaratively create these service instances and their credentials as Kubernetes resources.
The provider
section specifies details of the provider subaccount linked to this application, while globalAccountId
denotes the global account in which the provider subaccount is created. Within a global account, the btpAppName
has to be unique as this is equivalent to XSAPPNAME
, which is used in various SAP BTP service and application constructs.
The domains
section provides details of where the application routes are exposed. Within a “Gardener” cluster, the primary application domain is a subdomain of the cluster domain, and “Gardener” cert-management will be used to request a wildcard TLS certificate for the primary domain. Additional secondary domains may also be specified (for example, for customer-specific domains) for the application.
NOTE: While the same secondary domain can technically be used across applications; the consumers need to ensure that the tenant sub-domains are unique across such applications that share the same domain!
istioIngressGatewayLabels
are key-value pairs (string) used to identify the ingress controller component of Istio and the related load balancer service. These values are configured during the installation of Istio service mesh in the cluster.
7.2 - CAPApplicationVersion
CAPApplicationVersion
resourceThe CAPApplicationVersion
has the following high level structure:
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
name: cav-cap-app-v1
namespace: cap-ns
spec:
version: 3.2.1 # <-- semantic version (must be unique within the versions of a CAP application)
capApplicationInstance: cap-app
registrySecrets: # <-- image pull secrets to be used in the workloads
- regcred
workloads: # <-- define deployments and jobs used for this application version
- name: "cap-backend"
deploymentDefinition: # ...
consumedBTPServices: # ...
- name: "app-router"
deploymentDefinition: # ...
consumedBTPServices: # ...
- name: "service-content"
jobDefinition: # ...
consumedBTPServices: # ...
- name: "tenant-operation"
jobDefinition: # ...
consumedBTPServices: # ...
tenantOperations: # ... <-- (optional)
- An instance of
CAPApplicationVersion
is always related to an instance ofCAPApplication
in the same namespace. This reference is established using the attributecapApplicationInstance
. - An array of workloads (
workloads
) must be defined that include the various software components of the SAP Cloud Application Programming Model application. A deployment representing the CAP application server or a job that which is used for tenant operations are examples of such workloads. A workload must have either adeploymentDefinition
or ajobDefinition
. See the next section for more details. - An optional attribute
tenantOperations
can be used to define a sequence of steps (jobs) to be executed during tenant operations (provisioning / upgrade / deprovisioning).
The
CAPApplicationVersion
resource is meant to be immutable - it’s spec should not be modified once it is deployed. This is also prevented by our web-hooks which we recommend to always keep active (default).
Workloads with deploymentDefinition
name: cap-backend
consumedBTPServices: # <-- an array of service instance names referencing the SAP BTP services defined in the CAPApplication resource
- cap-uaa
- cap-saas-reg
deploymentDefinition:
type: CAP # <-- possible values are CAP / Router / Additional
image: some.repo.example.com/cap-app/server:3.22.11 # <-- container image
env: # <-- (optional) same as in core v1 pod.spec.containers.env
- name: SAY
value: "I'm GROOT"
replicas: 3 # <-- (optional) replicas for scaling
ports:
- name: app-port
port: 4004
routerDestinationName: cap-server-url
- name: tech-port
port: 4005
monitoring:
scrapeConfig:
port: tech--port
deletionRules:
expression: scalar(sum(avg_over_time(current_sessions{job="cav-cap-app-v1-cap-backend-svc",namespace="cap-ns"}[2h]))) <= bool 5
The type
of the deployment is important to indicate how the operator handles this workload (for example, injection of destinations
to be used by the approuter). Valid values are:
CAP
to indicate a CAP application server. Only one workload of this type can be used at present.Router
to indicate a version of AppRouter. Only one workload of this type can be used.Additional
to indicate supporting components that can be deployed along with the CAP application server.
You can define optional attributes such as replicas
, env
, resources
, probes
, securityContext
, initContainers
and ports
to configure the deployment.
Port configuration
It’s possible to define which (and how many) ports exposed by a deployment container are exposed inside the cluster (via services of type ClusterIP
). The port definition includes a name
in addition to the port
number being exposed.
For deploymentDefinition
, other than type Router
it would be possible to specify a routerDestinationName
which would be used as a named destination
injected into the approuter.
The port configurations aren’t mandatory and can be omitted. This would mean that the operator will configure services using defaults. The following defaults are applied if port configuration is omitted:
- For workload of type
CAP
, the default port used by CAP,4004
, will be added to the service and a destination with namesrv-api
will be added to the approuter referring to this service port (any existingdestinations
environment configuration for this workload will be taken over by overwriting theURL
). - For workload of type
Router
, the port5000
will be exposed in the service. This service will be used as the target for HTTP traffic reaching the application domain (domains are specified within theCAPApplication
resource).
NOTE: If multiple ports are configured for a workload of type
Router
, the first available port will be used to target external traffic to the application domain.
Monitoring configuration
For each workload of type deployment in a CAPApplicationVersion
, it is possible to define:
- Deletion rules: A criteria based on metrics which when satisfied signifies that the workload can be removed
- Scrape configuration: Configuration which defines how metrics are scraped from the workload service.
Details of how to configure workload monitoring can be found here.
Workloads with jobDefinition
workloads:
# ... deployment workloads have been omitted in this example
- name: "content-deployer"
consumedServices: # ...
jobDefinition:
type: Content
image: some.repo.example.com/cap-app/content:1.0.1
- name: "tenant-operation"
consumedServices: # ...
jobDefinition:
type: TenantOperation
image: some.repo.example.com/cap-app/server:3.22.11
backoffLimit: 2 # <-- determines retry attempts for the job on failure (default is 6)
ttlSecondsAfterFinished: 300 # <-- the job will be cleaned up after this duration
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
- name: "notify-upgrade"
consumedServices: # ...
jobDefinition:
type: CustomTenantOperation
image: # ...
command: ["npm", "run", "notify:upgrade"] # <-- custom entry point for the container allows reuse of a container image with multiple entry points
backoffLimit: 1
- name: "create-test-data"
consumedServices: # ...
jobDefinition:
type: CustomTenantOperation
image: # ...
command: ["npm", "run ", "deploy:testdata"]
Workloads with a jobDefinition
represent a job execution at a particular point in the lifecycle of the application or tenant. The following values are allowed for type
in such workloads:
Content
: A content deployer job that can be used to deploy (SAP BTP) service specific content from the application version. This job is executed as soon as a newCAPApplicationVersion
resource is created in the cluster. Multiple workloads of this type may be defined in theCAPApplicationVersion
and the order in which they are executed can be specified viaContentJobs
.TenantOperation
: A job executed during provisioning, upgrade, or deprovisioning of a tenant (CAPTenant
). These jobs are controlled by the operator and use thecds/mtxs
APIs to perform HDI content deployment by default. If a workload of typeTenantOperation
isn’t provided as part of theCAPApplicationVersion
, the workload withdeploymentDefinition
of typeCAP
will be used to determine thejobDefinition
(image
,env
, etc.). Also, ifcds/mtxs
APIs are used,command
can be used by applications to trigger tenant operations with custom command.CustomTenantOperation
: An optional job which runs before or after theTenantOperation
where the application can perform tenant-specific tasks (for example, create test data).
Sequencing tenant operations
A tenant operation refers to provisioning
, upgrade
or deprovisioning
which are executed in the context of a CAP application for individual tenants (i.e. using the cds/mtxs
or similar modules provided by CAP). Within the workloads
, we have already defined two types of jobs that are valid for such operations, namely TenantOperation
and CustomTenantOperation
.
The TenantOperation
is mandatory for all tenant operations.
In addition, you can choose which CustomTenantOperation
jobs run for a specific operation and in which order. For example, a CustomTenantOperation
deploying test data to the tenant database schema would need to run during provisioning
, but must not run during deprovisioning
.
The field tenantOperations
specifies which jobs are executed during the different tenant operations and the order they are executed in.
spec:
workloads: # ...
tenantOperations:
provisioning:
- workloadName: "tenant-operation"
- workloadName: "create-test-data"
upgrade:
- workloadName: "notify-upgrade"
continueOnFailure: true # <-- indicates the overall operation may proceed even if this step fails
- workloadName: "tenant-operation"
- workloadName: "create-test-data"
# <-- as the deprovisioning steps are not specified, only the `TenantOperation` workload (first available) will be executed
In the example above, for each tenant operation, not only are the valid jobs (steps) specified, but also the order in which they are to be executed. Each step in an operation is defined with:
workloadName
refers to the job workload executed in this operation stepcontinueOnFailure
is valid only forCustomTenantOperation
steps and indicates whether the overall tenant operation can proceed when this operation step fails.
NOTE:
- Specifying
tenantOperations
is required only ifCustomTenantOperations
are to be used. If not specified, each operation will comprise of only theTenantOperation
step (the first one available fromworkloads
).- The
tenantOperations
and specified sequencing are valid only for tenants provisioned (or deprovisioned) on the correspondingCAPApplicationVersion
and for tenants being upgraded to thisCAPApplicationVersion
.
Sequencing content jobs
When you create a CAPApplicationVersion
workload, you can define multiple content jobs. The order in which these jobs are executed is important, as some jobs may depend on the output of others. The ContentJobs
property allows you to specify the order in which content jobs are executed.
spec:
workloads: # ...
tenantOperations: # ...
contentJobs:
- content-deployer-service
- content-deployer-ui
Full Example
apiVersion: sme.sap.com/v1alpha1
kind: CAPApplicationVersion
metadata:
name: cav-cap-app-v1
namespace: cap-ns
spec:
version: 3.2.1
capApplicationInstance: cap-app
registrySecrets:
- regcred
workloads:
- name: cap-backend
consumedBTPServices:
- cap-uaa
- cap-service-manager
- cap-saas-reg
deploymentDefinition:
type: CAP
image: some.repo.example.com/cap-app/server:3.22.11
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
replicas: 3
ports:
- name: app-port
port: 4004
routerDestinationName: cap-server-url
- name: tech-port
port: 4005
appProtocol: grpc
monitoring:
scrapeConfig:
port: tech--port
deletionRules:
expression: scalar(sum(avg_over_time(current_sessions{job="cav-cap-app-v1-cap-backend-svc",namespace="cap-ns"}[2h]))) <= bool 5
livenessProbe:
failureThreshold: 3
httpGet:
path: /
port: 4005
initialDelaySeconds: 20
periodSeconds: 10
timeoutSeconds: 2
readinessProbe:
failureThreshold: 3
httpGet:
path: /
port: 4005
initialDelaySeconds: 20
periodSeconds: 10
timeoutSeconds: 2
resources:
limits:
cpu: 200m
memory: 500Mi
requests:
cpu: 20m
memory: 50Mi
securityContext:
runAsUser: 1000
runAsGroup: 2000
- name: "app-router"
consumedBTPServices:
- cap-uaa
- cap-saas-reg
- cap-html5-repo-rt
deploymentDefinition:
type: Router
image: some.repo.example.com/cap-app/router:4.0.1
env:
- name: PORT
value: "3000"
ports:
- name: router-port
port: 3000
livenessProbe:
failureThreshold: 3
httpGet:
path: /
port: 3000
initialDelaySeconds: 20
periodSeconds: 10
timeoutSeconds: 2
readinessProbe:
failureThreshold: 3
httpGet:
path: /
port: 3000
initialDelaySeconds: 20
periodSeconds: 10
timeoutSeconds: 2
resources:
limits:
cpu: 200m
memory: 500Mi
requests:
cpu: 20m
memory: 50Mi
podSecurityContext:
runAsUser: 2000
fsGroup: 2000
- name: "service-content"
consumedServices:
- cap-uaa
- cap-portal
- cap-html5-repo-host
jobDefinition:
type: Content
image: some.repo.example.com/cap-app/content:1.0.1
securityContext:
runAsUser: 1000
runAsGroup: 2000
- name: "ui-content"
consumedServices:
- cap-uaa
- cap-portal
- cap-html5-repo-host
jobDefinition:
type: Content
image: some.repo.example.com/cap-app/ui-content:1.0.1
securityContext:
runAsUser: 1000
runAsGroup: 2000
- name: "tenant-operation"
consumedServices: # ...
jobDefinition:
type: TenantOperation
image: some.repo.example.com/cap-app/server:3.22.11
backoffLimit: 2
ttlSecondsAfterFinished: 300
env:
- name: CDS_ENV
value: production
- name: CDS_MTX_PROVISIONING_CONTAINER
value: '{"provisioning_parameters": { "database_id": "16e25c51-5455-4b17-a4d7-43545345345"}}'
- name: "notify-upgrade"
consumedServices: []
jobDefinition:
type: CustomTenantOperation
image: some.repo.example.com/cap-app/server:3.22.11
command: ["npm", "run", "notify:upgrade"]
backoffLimit: 1
- name: "create-test-data"
consumedServices:
- cap-service-manager
jobDefinition:
type: CustomTenantOperation
image: some.repo.example.com/cap-app/server:3.22.11
command: ["npm", "run ", "deploy:testdata"]
tenantOperations:
provisioning:
- workloadName: "tenant-operation"
- workloadName: "create-test-data"
upgrade:
- workloadName: "notify-upgrade"
continueOnFailure: true
- workloadName: "tenant-operation"
- workloadName: "create-test-data"
contentJobs:
- service-content
- ui-content
NOTE: The CAP Operator workloads supports several configurations (present in the kubernetes API), which can be configured by looking into our API reference:
- Container API reference for generic container-specific configuration
- Deployment API reference for deployment-specific configuration
- Job API reference for job-specific configuration
The supported configurations is kept minimal intentionally to keep the overall API simple by considering commonly used configurations.
Note: For
initContainers
nearly the same environment variables as the main container are made available including VCAP_SERVICES environment.
7.3 - CAPTenant
CAPTenant
resourceWarning
TheCAPTenant
resource is completely managed by CAP Operator and must not be created or modified manually. For details of how CAPTenant
is created, see tenant subscription.The CAPTenant
resource indicates the existence of a tenant in the related application (or one that is current being provisioned). The resource starts with a Provisioning
state and moves to Ready
when successfully provisioned. Managing tenants as Kubernetes resources allows you not only to control the lifecycle of the entity, but also allows you to control other requirements that must be fulfilled for the application to serve tenant-specific requests (for example, creating of networking resources).
apiVersion: sme.sap.com/v1alpha1
kind: CAPTenant
metadata:
name: cap-app-consumer-ge455
namespace: cap-ns
spec:
capApplicationInstance: cap-app
subDomain: consumer-x
tenantId: cb46733-1279-48be-fdf434-aa2bae55d7b5
version: "1"
versionUpgradeStrategy: always
The specification contains attributes relevant for SAP BTP, which identifies a tenant such as tenantId
and subDomain
.
The version
field corresponds to the CAPApplicationVersion
on which the tenant is provisioned or was upgraded. When a newer CAPApplicationVersion
is available, the operator automatically increments the tenant version, which triggers the upgrade process. The versionUpgradeStrategy
is by default always
, but can be set to never
in exceptional cases to prevent an automatic upgrade of the tenant.
7.4 - CAPTenantOperation
CAPTenantOperation
resourceWarning
TheCAPTenantOperation
resource is managed by CAP Operator and must not be created or modified manually. The creation of CAPTenantOperation
is initiated by the CAPTenant
for executing provisioning, deprovisioning, or upgrade.apiVersion: sme.sap.com/v1alpha1
kind: CAPTenantOperation
metadata:
name: cap-app-consumer-ge455-77kb9
namespace: cap-ns
spec:
capApplicationVersionInstance: cav-cap-app-v2
operation: upgrade
steps:
- continueOnFailure: true
name: tenant-operation
type: CustomTenantOperation
- name: tenant-operation
type: TenantOperation
- name: create-test-data
type: CustomTenantOperation
subDomain: consumer-x
tenantId: cb46733-1279-48be-fdf434-aa2bae55d7b5
The example above shows a CAPTenantOperation
created to execute an upgrade operation on a tenant. In addition to tenant details, the CAPApplicationVersion
to be used for the operation is specified. In case of upgrade or a provisioning operation, this would be the target CAPApplicationVersion
whereas for deprovisioning, it would be the current CAPApplicationVersion
of the tenant.
The operation is completed by executing a series of steps (jobs) which are specified in or derived from the CAPApplicationVersion
. Each step refers to a workload of type TenantOperation
or CustomTenantOperation
. When CAPTenantOperation
is created by CAP Pperator, there must be at least one step of type TenantOperation
(which is the job used for the database schema update using CAP provided modules).
CustomTenantOperation
jobs are hooks provided to the application, which can be executed before or after the actual TenantOperation
. For applications to be able to identify the context of an execution, each job is injected with the following environment variables:
CAPOP_APP_VERSION
: The (semantic) version from the relevantCAPApplicationVersion
CAPOP_TENANT_ID
: Tenant identifier of the tenant for which the operation is executedCAPOP_TENANT_OPERATION
: The type of operation -provisioning
,deprovisioning
, orupgrade
CAPOP_TENANT_SUBDOMAIN
: Subdomain (from subaccount) belonging to the tenant for which the operation is executedCAPOP_TENANT_TYPE
: The type of tenant -provider
orconsumer
CAPOP_APP_NAME
: The BTP App Name from the correspondingCAPApplication
configurationCAPOP_GLOBAL_ACCOUNT_ID
: The Global Account Identifier from the correspondingCAPApplication
configurationCAPOP_PROVIDER_TENANT_ID
: The provider tenant identifier from the correspondingCAPApplication
configurationCAPOP_PROVIDER_SUBDOMAIN
: The provider tenant subdomain from the correspondingCAPApplication
configuration
Note that all of the above environment variables are also made available on the corresponding initContainers
(along with other relevant VCAP_SERVICES
credentials)
7.5 - CAPTenantOutput
CAPTenantOutput
resourceThe CAPTenantOutput
may be used to add additional data to the asynchronous callback parameters from the SaaS provisioning service during tenant onboarding. The resource is not reconciled but just consumed by the subscription server to generate additional data. It has the following structure:
apiVersion: sme.sap.com/v1alpha1
kind: CAPTenantOutput
metadata:
name: cap-app-consumer-output
namespace: cap-ns
labels:
sme.sap.com/btp-tenant-id: cb46733-1279-48be-fdf434-aa2bae55d7b5
spec:
subscriptionCallbackData: '{foo: bar}'
The example above shows an instance of the resource that is associated with a tenant via the sme.sap.com/btp-tenant-id
label (which must be set by consumers).
Warning
The resource is meant to be created/updated during tenant operations for e.g. the ones created during tenant onboarding. As of now, the primary intention of this resource is to enhance the parameters of subscription callback during tenant onboarding. But the resources may be used for further scenarios in the future.
Any RBAC related updates needed to create/modify the resources for e.g. in a custom tenant operation needs to be handled by consumers and assigned to the relevant job via serviceAccountName
config for that workload (job).
Note that all instances of this resources found for a given tenant will be cleaned up before any CAPTenantOperation
is created.