🕑Ephemeral Agents
This feature is supported from version 2.22.0
The following will explain how to run the executor component in"ephemeral"
mode.
These environment variables can be used to customize the API component:
ExecutorEphemeralNamespace (Default value: "terrakube")
ExecutorEphemeralImage (Defatul value: "azbuilder/executor:2.22.0" )
ExecutorEphemeralSecret (Default value: "terrakube-executor-secrets" )
The above is basically to control where the job will be created and executed and to mount the secrets required by the executor component
Internally the Executor component will use the following to run in "ephemeral"
:
EphemeralFlagBatch (Default value: "false")
EphemeralJobData, this contains all the data that the executor need to run.
Requirements
To use Ephemeral executors we need to create the following configuration:
Service Account Creation
apiVersion: v1
kind: ServiceAccount
metadata:
name: terrakube-api-service-account
namespace: terrakube
Role Creation
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
namespace: terrakube
name: terrakube-api-role
rules:
- apiGroups: ["batch"]
resources: ["jobs"]
verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
Role Binding Creation
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: terrakube-api-role-binding
namespace: terrakube
subjects:
- kind: ServiceAccount
name: terrakube-api-service-account
namespace: terrakube
roleRef:
kind: Role
name: terrakube-api-role
apiGroup: rbac.authorization.k8s.io
Helm Chart Configuration
Once the above configuration is created we can deploy the Terrakube API like the following example:
## API properties
api:
image: "azbuilder/api-server"
version: "2.22.0"
serviceAccountName: "terrakube-api-service-account"
env:
- name: ExecutorEphemeralNamespace
value: terrakube
- name: ExecutorEphemeralImage
value: azbuilder/executor:2.22.0
- name: ExecutorEphemeralSecret
value: terrakube-executor-secrets
Workspace Configuration
Add the environment variable TERRAKUBE_ENABLE_EPHEMERAL_EXECUTOR=1
like the image below

Workspace Execution
Now when the job is running internally Terrakube will create a K8S job and will execute each step of the job in a "ephemeral executor"

Internal Kubernetes Job Example:

Plan Running in a pod:

Apply Running in a different pod:

Node Selector.
If required you can specify the node selector configuration where the pod will be created using something like the following:
api:
env:
- name: JAVA_TOOL_OPTIONS
value: "-Dorg.terrakube.executor.ephemeral.nodeSelector.diskType=ssd -Dorg.terrakube.executor.ephemeral.nodeSelector.nodeType=spot"
The above will be the equivalent to use the Kubernetes YAML like:
nodeSelector:
disktype: ssd
nodeType: spot
Adding node selector configuration is available from version 2.23.0
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