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Posted to user@flink.apache.org by Salva Alcántara <sa...@gmail.com> on 2023/04/17 09:47:25 UTC
Integrating Flink with Linkerd
I am deploying some Flink jobs which require access to some services under
a service mesh implemented via Linkerd. From time to time, I'm running into
this error:
```
java.lang.NoClassDefFoundError: Could not initialize class foo.bar.Job
```
It's weird because I have some jobs running well but others for which I am
getting this error. I can confirm that the jar file contains the class that
cannot be found apparently, so it's not a problem with the jar itself, but
seems to be related with linkerd. In particular, I'm using the following
pod annotations for both the jobmanager and the taskmanager pods (taken
from my Helm Chart values file):
```
podAnnotations:
linkerd.io/inject: enabled
config.linkerd.io/skip-outbound-ports: 6123,6124
config.linkerd.io/proxy-await: enabled
```
For what it's worth, I'm using the [Ververica Platform][1] (Community
Edition) for deploying my jobs to Kubernetes (although I don't think that
the main issue is specific to the VVP):
```
{{- define "vvp.deployment" }}
kind: Deployment
apiVersion: v1
metadata:
name: my-job
spec:
template:
spec:
artifact:
kind: jar
flinkImageRegistry: {{ .Values.flink.imageRegistry }}
flinkVersion: "1.15.1"
flinkImageTag: 1.15.1-stream1-scala_2.12-java11-linkerd
entryClass: foo.bar.Job
kubernetes:
jobManagerPodTemplate:
metadata:
{{- with .Values.flink.podAnnotations }}
annotations:
{{- toYaml . | nindent 14 }}
{{- end }}
spec:
containers:
- name: flink-jobmanager
command:
- linkerd-entrypoint.sh
taskManagerPodTemplate:
metadata:
{{- with .Values.flink.podAnnotations }}
annotations:
{{- toYaml . | nindent 14 }}
{{- end }}
{{- end }}
```
where the contents of `linkered-entrypoint.sh` are:
```
#!/bin/bash
set -e
exec linkerd-await --shutdown -- "$@"
```
For extra context, the VVP and the flink jobs are deployed into different
namespaces. Also, for the VVP pods, I'm not using any linkerd annotations
whatsoever.
To be clear, if I remove the annotations / everything releated to Linkerd,
the job deployment works as expected.
Has anyone encountered similar problems? Am I missing something? Should I
also use the ` linkerd.io/inject: enabled` annotation for the VVP pods?
The closest troubleshooting resource/guide that I've found so far is [this
one][2], which targets Istio instead of Linkerd.
[1]: https://www.ververica.com/
[2]:
https://ververica.zendesk.com/hc/en-us/articles/7233687970460-How-to-integrate-Istio-with-Ververica-Platform
---
PS: Also posted in SO:
- https://stackoverflow.com/questions/76033732/flink-kubernetes-and-linkerd
Re: Integrating Flink with Linkerd
Posted by Shammon FY <zj...@gmail.com>.
Hi Salva
I think you can check whether `foo.bar.Job` is in the classpath of your
job. “java.lang.NoClassDefFoundError: Could not initialize class
foo.bar.Job” error usually occurs when this class is not in the classpath
Best,
Shammon FY
On Mon, Apr 17, 2023 at 5:48 PM Salva Alcántara <sa...@gmail.com>
wrote:
> I am deploying some Flink jobs which require access to some services under
> a service mesh implemented via Linkerd. From time to time, I'm running into
> this error:
>
> ```
> java.lang.NoClassDefFoundError: Could not initialize class foo.bar.Job
> ```
>
> It's weird because I have some jobs running well but others for which I am
> getting this error. I can confirm that the jar file contains the class that
> cannot be found apparently, so it's not a problem with the jar itself, but
> seems to be related with linkerd. In particular, I'm using the following
> pod annotations for both the jobmanager and the taskmanager pods (taken
> from my Helm Chart values file):
>
> ```
> podAnnotations:
> linkerd.io/inject: enabled
> config.linkerd.io/skip-outbound-ports: 6123,6124
> config.linkerd.io/proxy-await: enabled
> ```
>
> For what it's worth, I'm using the [Ververica Platform][1] (Community
> Edition) for deploying my jobs to Kubernetes (although I don't think that
> the main issue is specific to the VVP):
>
> ```
> {{- define "vvp.deployment" }}
> kind: Deployment
> apiVersion: v1
> metadata:
> name: my-job
> spec:
> template:
> spec:
> artifact:
> kind: jar
> flinkImageRegistry: {{ .Values.flink.imageRegistry }}
> flinkVersion: "1.15.1"
> flinkImageTag: 1.15.1-stream1-scala_2.12-java11-linkerd
> entryClass: foo.bar.Job
> kubernetes:
> jobManagerPodTemplate:
> metadata:
> {{- with .Values.flink.podAnnotations }}
> annotations:
> {{- toYaml . | nindent 14 }}
> {{- end }}
> spec:
> containers:
> - name: flink-jobmanager
> command:
> - linkerd-entrypoint.sh
> taskManagerPodTemplate:
> metadata:
> {{- with .Values.flink.podAnnotations }}
> annotations:
> {{- toYaml . | nindent 14 }}
> {{- end }}
> {{- end }}
> ```
>
> where the contents of `linkered-entrypoint.sh` are:
>
> ```
> #!/bin/bash
> set -e
> exec linkerd-await --shutdown -- "$@"
> ```
>
> For extra context, the VVP and the flink jobs are deployed into different
> namespaces. Also, for the VVP pods, I'm not using any linkerd annotations
> whatsoever.
>
> To be clear, if I remove the annotations / everything releated to Linkerd,
> the job deployment works as expected.
>
> Has anyone encountered similar problems? Am I missing something? Should I
> also use the ` linkerd.io/inject: enabled` annotation for the VVP pods?
> The closest troubleshooting resource/guide that I've found so far is [this
> one][2], which targets Istio instead of Linkerd.
>
> [1]: https://www.ververica.com/
> [2]:
> https://ververica.zendesk.com/hc/en-us/articles/7233687970460-How-to-integrate-Istio-with-Ververica-Platform
>
> ---
>
> PS: Also posted in SO:
> -
> https://stackoverflow.com/questions/76033732/flink-kubernetes-and-linkerd
>