Redeploy/Restart an Application
A KeptnApp can fail because of an unsuccessful pre-deployment evaluation or pre-deployment task. For example, this happens if the target value of a KeptnEvaluationDefinition resource is misconfigured or a pre-deployment evaluation checks the wrong URL.
After you fix the configuration
that caused the pre-deployment evaluation or task to fail,
you can increment the spec.revision value
and apply the updated KeptnApp manifest
to create a new revision of the KeptnApp
without modifying the version.
Afterwards, all related KeptnWorkloadVersions
automatically refer to the newly created revision of the KeptnAppVersion
to determine whether they are allowed
to enter their respective deployment phases.
To illustrate this, consider the following example:
apiVersion: v1
kind: Namespace
metadata:
name: restartable-apps
annotations:
keptn.sh/lifecycle-toolkit: "enabled"
---
apiVersion: lifecycle.keptn.sh/v1alpha2
kind: KeptnApp
metadata:
name: podtato-head
namespace: restartable-apps
spec:
version: "0.1.1"
revision: 1
workloads:
- name: podtato-head-entry
version: "0.1.2"
preDeploymentTasks:
- pre-deployment-check
---
apiVersion: lifecycle.keptn.sh/v1alpha2
kind: KeptnTaskDefinition
metadata:
name: pre-deployment-check
namespace: restartable-apps
spec:
function:
inline:
code: |
console.error("I failed")
process.exit(1)
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: podtato-head-entry
namespace: restartable-apps
labels:
app: podtato-head
spec:
selector:
matchLabels:
component: podtato-head-entry
template:
metadata:
labels:
component: podtato-head-entry
keptn.sh/workload: podtato-head-entry
keptn.sh/app: podtato-head
keptn.sh/version: "0.1.2"
spec:
terminationGracePeriodSeconds: 5
containers:
- name: server
image: ghcr.io/podtato-head/entry:0.2.7
imagePullPolicy: Always
ports:
- containerPort: 9000
env:
- name: PODTATO_PORT
value: "9000"
In this example, the KeptnApp executes a pre-deployment check
which clearly fails because of the pre-deployment-check task,
and therefore is not able to proceed with the deployment.
After applying this manifest,
you can inspect the status of the created KeptnAppVersion:
$ kubectl get keptnappversions.lifecycle.keptn.sh -n restartable-apps
NAME APPNAME VERSION PHASE
podtato-head-0.1.1-1 podtato-head 0.1.1 AppPreDeployTasks
Notice that the KeptnAppVersion stays
in the AppPreDeployTasks phase for a while,
due to the pre-check trying to run
until the failure threshold is reached.
Eventually, the KeptnAppVersion’s PredeploymentPhase
is in a Failed state, with the remaining phases being Deprecated.
$ kubectl get keptnappversions.lifecycle.keptn.sh -n restartable-apps -owide
NAME APPNAME VERSION PHASE PREDEPLOYMENTSTATUS PREDEPLOYMENTEVALUATIONSTATUS WORKLOADOVERALLSTATUS POSTDEPLOYMENTSTATUS POSTDEPLOYMENTEVALUATIONSTATUS
podtato-head-0.1.1-1 podtato-head 0.1.1 AppPreDeployTasks Failed Deprecated Deprecated Deprecated Deprecated
To fix the deployment of this application,
we first need to fix the task that has failed earlier.
To do so, edit the pre-deployment-check KeptnTaskDefinition:
kubectl -n restartable-apps edit keptntaskdefinitions.lifecycle.keptn.sh pre-deployment-check
Modify the manifest to look like this:
apiVersion: lifecycle.keptn.sh/v1alpha2
kind: KeptnTaskDefinition
metadata:
name: pre-deployment-check
namespace: restartable-apps
spec:
function:
inline:
code: |
console.error("Success")
To restart the deployment of our KeptnApplication,
edit the manifest:
kubectl -n restartable-apps edit keptnapps.lifecycle.keptn.sh podtato-head
Increment the value of the spec.revision field by one:
apiVersion: lifecycle.keptn.sh/v1alpha2
kind: KeptnApp
metadata:
name: podtato-head
namespace: restartable-apps
spec:
version: "0.1.1"
revision: 2 # Increased this value from 1 to 2
workloads:
- name: podtato-head-entry
version: "0.1.2"
preDeploymentTasks:
- pre-deployment-check
After those changes have been made,
you will notice a new revision of the podtato-head KeptnAppVersion:
$ kubectl get keptnappversions.lifecycle.keptn.sh -n restartable-apps
NAME APPNAME VERSION PHASE
podtato-head-0.1.1-1 podtato-head 0.1.1 AppPreDeployTasks
podtato-head-0.1.1-2 podtato-head 0.1.1 AppDeploy
See that the newly created revision podtato-head-0.1.1-2
has made it beyond the pre-deployment check phase
and has reached its AppDeployPhase.
You can also verify the execution of the pre-deployment-check
by retrieving the list of KeptnTasks in
the restartable-apps namespace:
$ kubectl get keptntasks.lifecycle.keptn.sh -n restartable-apps
NAME APPNAME APPVERSION WORKLOADNAME WORKLOADVERSION JOB NAME STATUS
pre-pre-deployment-check-49827 podtato-head 0.1.1 klc-pre-pre-deployment-check--77601 Failed
pre-pre-deployment-check-65056 podtato-head 0.1.1 klc-pre-pre-deployment-check--57313 Succeeded
Notice that the previous failed instances are still available
for both KeptnAppVersions and KeptnTasks.
This may be useful historical data to keep track of
what went wrong during earlier deployment attempts.