Linkerd2: "linkerd inject" does not work on cronjobs?

Created on 23 Oct 2019 · 4Comments · Source: linkerd/linkerd2

Bug Report

What is the issue?

Trying to use linkerd inject to annotate a cronjob yaml and it returns "!! no supported object found"

How can it be reproduced?

Create a cronjob yaml, apply it, then:

kubectl get cronjobs.batch mssql-backup -o yaml | linkerd inject -

Logs, error output, etc

(apologies for the debugging code in the sample)

$ kubectl get cronjobs.batch mssql-backup -o yaml | linkerd inject  -
apiVersion: batch/v1beta1
kind: CronJob
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"batch/v1beta1","kind":"CronJob","metadata":{"annotations":{},"name":"mssql-backup","namespace":"se"},"spec":{"concurrencyPolicy":"Forbid","failedJobsHistoryLimit":1,"jobTemplate":{"spec":{"template":{"spec":{"containers":[{"args":["echo \"hello world\"; /opt/mssql-tools/bin/sqlcmd -S server -U sa -P password -I -Q \"EXEC sp_msForEachDB 'PRINT ''?'' ';\" | while read dbname; do echo \"*** Backing up $dbname ***\"; /opt/mssql-tools/bin/sqlcmd -S server -U sa -P password -I -Q \"BACKUP DATABASE master TO DISK='/mssql-backup/backup/$dbname/$dbname-$(date +%Y-%m-%d.%s).bak' WITH STATS, COMPRESSION;\" ; done; echo \"*** End of $dbname backup ***\"; echo \"\"; sleep 60; echo \" *** NORMAL TERMINATION *** \";"],"command":["bash","-c"],"image":"microsoft/mssql-tools","name":"mssql-backup"}],"nodeSelector":{"kubernetes.io/os":"linux"},"restartPolicy":"Never","securityContext":{"fsGroup":0,"runAsUser":0}}}}},"schedule":"*/5 * * * *","successfulJobsHistoryLimit":3}}
  creationTimestamp: "2019-10-23T20:03:48Z"
  name: mssql-backup
  namespace: se
  resourceVersion: "2061027"
  selfLink: /apis/batch/v1beta1/namespaces/se/cronjobs/mssql-backup
  uid: 399f4b60-f5d0-11e9-a92d-72a7270cd27e
spec:
  concurrencyPolicy: Forbid
  failedJobsHistoryLimit: 1
  jobTemplate:
    metadata:
      creationTimestamp: null
    spec:
      template:
        metadata:
          creationTimestamp: null
        spec:
          containers:
          - args:
            - echo "hello world"; /opt/mssql-tools/bin/sqlcmd -S server
              -U sa -P password -I -Q "EXEC sp_msForEachDB
              'PRINT ''?'' ';" | while read dbname; do echo "*** Backing up $dbname
              ***"; /opt/mssql-tools/bin/sqlcmd -S server -U sa -P password
              -I -Q "BACKUP DATABASE master TO DISK='/mssql-backup/backup/$dbname/$dbname-$(date
              +%Y-%m-%d.%s).bak' WITH STATS, COMPRESSION;" ; done; echo "*** End of
              $dbname backup ***"; echo ""; sleep 60; echo " *** NORMAL TERMINATION
              *** ";
            command:
            - bash
            - -c
            image: microsoft/mssql-tools
            imagePullPolicy: Always
            name: mssql-backup
            resources: {}
            terminationMessagePath: /dev/termination-log
            terminationMessagePolicy: File
          dnsPolicy: ClusterFirst
          nodeSelector:
            kubernetes.io/os: linux
          restartPolicy: Never
          schedulerName: default-scheduler
          securityContext:
            fsGroup: 0
            runAsUser: 0
          terminationGracePeriodSeconds: 30
  schedule: '*/5 * * * *'
  successfulJobsHistoryLimit: 3
  suspend: false
status:
  active:
  - apiVersion: batch/v1
    kind: Job
    name: mssql-backup-1571861700
    namespace: se
    resourceVersion: "2061025"
    uid: f8bae702-f5d1-11e9-a92d-72a7270cd27e
  lastScheduleTime: "2019-10-23T20:15:00Z"
---

‼ no supported objects found

cronjob "mssql-backup" skipped

`linkerd check` output

```$ linkerd check

kubernetes-api

√ can initialize the client
√ can query the Kubernetes API

kubernetes-version

√ is running the minimum Kubernetes API version
√ is running the minimum kubectl version

linkerd-config

√ control plane Namespace exists
√ control plane ClusterRoles exist
√ control plane ClusterRoleBindings exist
√ control plane ServiceAccounts exist
√ control plane CustomResourceDefinitions exist
√ control plane MutatingWebhookConfigurations exist
√ control plane ValidatingWebhookConfigurations exist
√ control plane PodSecurityPolicies exist

linkerd-existence

√ 'linkerd-config' config map exists
√ heartbeat ServiceAccount exist
√ control plane replica sets are ready
√ no unschedulable pods
√ controller pod is running
√ can initialize the client
√ can query the control plane API

linkerd-api

√ control plane pods are ready
√ control plane self-check
√ [kubernetes] control plane can talk to Kubernetes
√ [prometheus] control plane can talk to Prometheus
√ no invalid service profiles

linkerd-version

√ can determine the latest version
√ cli is up-to-date

control-plane-version

√ control plane is up-to-date
√ control plane and cli versions match

Status check results are √

$ linkerd version
Client version: stable-2.6.0
Server version: stable-2.6.0
```

Environment

Kubernetes Version: 1.14.6
Cluster Environment: AKS
Host OS: AKS Linux (Ubuntu?)
Linkerd version: 2.6-stable

Possible solution

Additional context

This is actually to add the annotation to end up "disable"ing the auto-proxy-inject until we figure out how to ask the sidecar to exit when the main container is done.

arecli good first issue help wanted

Source

geekmush

All 4 comments

As of now, linkerd inject does not support configs of Kind Cronjob.

As per the cases listed under method conf.getFreshWorkloadObj() (at pkg/inject/inject.go), nil is returned while trying to parse a config of type Cronjob.
Neither is method conf.parse() setup to process a config of this kind.

Once we have that, such a config can be unmarshalled to *ResourceConfig, have the annotations appended and marshalled back to yaml.

This would however be a cool feature to have.
@grampelberg @ihcsim WDYT?

This feature is very similar to https://github.com/linkerd/linkerd2/pull/3607