When using multiple replica for a deployment, synchronization only applies to one pod

[timofriedlberlin]

What happened?
I am using a deployment with multiple replicas:

- name: proxy
    helm:
      componentChart: true
      values:
        replicas: 2
        containers:
          - image: proxy

After changing some source files for the project, the application rebuilds and the sync is triggered.
But, only one of the Pods will be synchronized and restarted.

What did you expect to happen instead?
When using something like

sync:
    - labelSelector:
        app.kubernetes.io/component: proxy
      excludePaths:
        - .git/
        - src/
      uploadExcludePaths:
        - devspace.yaml
      onUpload:
        restartContainer: true
      waitInitialSync: true

I would expect all pods to be synchronized matching the label selector.

How can we reproduce the bug? (as minimally and precisely as possible)
Create some setup which verifies synchronization works, then change deployment.replicas > 1

Local Environment:

• DevSpace Version: 5.5.0
• Operating System: linux
• Deployment method: helm
  Kubernetes Cluster:
• Cloud Provider: k3s
• Kubernetes Version: v1.19.4

Anything else we need to know?

/kind bug

[timofriedlberlin]

I have found a workaround, I am posting it here because it shows my use-case:

#/bin/env bash
set -e

# sync
# - do a manual devspace sync
# - trigger a restart with devspace restartHelper
sync(){
  pod=${1}
  container=${2}
  echo "sync pod [$pod] ..."
  devspace sync --silent --pod $pod --container $container --upload-only --no-watch

  PID=$(kubectl exec $pod --container $container -- cat /.devspace/devspace-pid)
  kubectl exec $pod --container $container -- rm /.devspace/devspace-pid
  kubectl exec $pod --container $container -- kill -9 $PID
  echo "sync pod [$pod] done"
}

# obtain a list of pods matching a name
getpods(){
  local name=$1
  local pods=$(kubectl get pods | grep -E $name | awk -F ' ' '{print $1}')
  echo $pods
}

# sync proxy/container-0
for pod in $(getpods proxy); do
  sync $pod container-0 &
done;

# sync asterisk/container-1
for pod  in $(getpods asterisk); do
  sync $pod container-1  &
done;

wait

[FabianKramm]

@timo-klarshift thanks for reporting this issue! Yes currently we do not support multiple replicas while syncing for devspace dev. We could think about adding that though. Your approach is kind of interesting in that you basically want a sync on demand which uploads the new files and then restarts the containers (btw you could use just kubectl exec $pod --container $container -- /tmp/devspacehelper restart instead of the other commands to restart the container), but I think this would require quite some changes in devspace to work with a single command

[timofriedlberlin]

@timo-klarshift thanks for reporting this issue! Yes currently we do not support multiple replicas while syncing for devspace dev. We could think about adding that though. Your approach is kind of interesting in that you basically want a sync on demand which uploads the new files and then restarts the containers (btw you could use just kubectl exec $pod --container $container -- /tmp/devspacehelper restart instead of the other commands to restart the container), but I think this would require quite some changes in devspace to work with a single command

Thanks for the quick answer! I am currently using the posted script in some npm script npm run dev - its triggered after the build process of my app and I currently disabled the devspace sync in devspace.yaml. Also thanks for pointing out /tmp/devspacehelper restart - Is that documented anywhere ? I found the way i do it now in some older docs from < 5.0

[FabianKramm]

@timo-klarshift I updated the docs page about how the restart helper works and how you can restart the container: https://devspace.sh/cli/docs/configuration/images/inject-restart-helper, which might be of interest for you

[matthew-muscat]

I've also run into this issue...

On a related note, it would be great if the sync action could be active across multiple images as well as the replicas within (currently, only the dev action will sync across multiple images)

Regarding syncing to multiple pods — I imagine one challenge in this implementation is that multiple containers would be responsible for both download + upload, potentially causing conflicts or loops in file activity.

An idea: The first replica sync would operate in upload / download mode, with additional replicas only operating in upload only mode

[deniseschannon]

Closing due to inactivity and the version used. If you are still facing this issue with our latest DevSpace version, please open a new issue.