kubectl replaced configmap built from directory does not show new content in a container

[sbezverk]

Running kubernetes 1.2.4. I build configmap from directory, where I store files required by the application using this command:
kubectl --server=http://10.57.120.10:8080 create configmap keystone-config --from-file=config/

in some cases I need to add file to the set of config files. So get yaml version of configmap, change it manually and then use kubectl replace to update it.
kubectl --server=http://10.57.120.10:8080 get configmap keystone-config -o yaml > keystone-config.yaml
change keystone-config.yaml following this file format
kubectl --server=http://10.57.120.10:8080 replace -f keystone-config.yaml

When I check the container I do not see any changes at the point where this configmap is mounted, but if I restart container then I see a new file which I manually added.

Please let me know if it is a bug or this way of changing configmap is not supported.

Thank you

Serguei

[vefimova]

Hi, I'm working on this one

[vefimova]

Hi, @sbezverk I didn't manage to reproduce bug following the steps you described on 1.2.4. Could you please provide more details for reproduction or confirm it was a confusion due to delayed update?

So what I did:

ConfigMap formed from dir:

# ls -la ../config-dir/

total 16
drwxr-xr-x 2 root root 4096 Jul  8 13:28 .
drwxr-xr-x 4 root root 4096 Jul  8 14:45 ..
-rw-r--r-- 1 root root   13 Jul  8 13:28 file1
-rw-r--r-- 1 root root   13 Jul  8 13:28 file2

# cat ../config-dir/file1

Hi i'm file1

# cat ../config-dir/file2

Hi i'm file2

# kubectl create configmap test-config --from-file=../config-dir/

configmap "test-config" created

# kubectl get configmap/test-config -o yaml > ../test-config.yaml

# cat test-config.yaml

apiVersion: v1
data:
  file1: |
    Hi i'm file1
  file2: |
    Hi i'm file2
kind: ConfigMap
metadata:
  creationTimestamp: 2016-07-08T14:42:20Z
  name: test-config
  namespace: default
  resourceVersion: "1954037"
  selfLink: /api/v1/namespaces/default/configmaps/test-config
  uid: 2ce38933-451a-11e6-8ed8-5254000d0846

# cat podConfigmap.yaml

apiVersion: v1
kind: Pod
metadata:
  name: dapi-test-pod
spec:
  containers:
    - name: test-container
      image: gcr.io/google_containers/busybox
      command: [ "/bin/sh", -c, 'while :; do cat /etc/config/file1; sleep 1; done']
      volumeMounts:
      - name: config-volume
        mountPath: /etc/config
  volumes:
    - name: config-volume
      configMap:
        name: test-config
  restartPolicy: Never

# kubectl create -f podConfigmap.yaml

pod "dapi-test-pod" created

Ok, now let's change configMap and replace it:

# cat test-config.yaml

apiVersion: v1
data:
  file3: |
    Hi i'm file3
    ;))))!!!!
  file1: |
    Hi i'm file1 !!!
  file2: |
    Hi i'm file2 !!!
kind: ConfigMap
metadata:
  creationTimestamp: 2016-07-08T14:42:20Z
  name: test-config
  namespace: default
  resourceVersion: "1954037"
  selfLink: /api/v1/namespaces/default/configmaps/test-config
  uid: 2ce38933-451a-11e6-8ed8-5254000d0846

# kubectl replace -f test-config.yaml

configmap "test-config" replaced

After replacement it will take some time kubelet to update files in mount path (~1 min):

# kubectl exec dapi-test-pod -- ls -la /etc/config/

total 4
drwxrwxrwt    3 root     root           140 Jul  8 14:45 .
drwxr-xr-x    7 root     root          4096 Jul  8 14:43 ..
drwxr-xr-x    2 root     root           100 Jul  8 14:45 ..7987_08_07_09_45_56.099037854
lrwxrwxrwx    1 root     root            31 Jul  8 14:45 ..data -> ..7987_08_07_09_45_56.099037854
lrwxrwxrwx    1 root     root            12 Jul  8 14:43 file1 -> ..data/file1
lrwxrwxrwx    1 root     root            12 Jul  8 14:43 file2 -> ..data/file2
lrwxrwxrwx    1 root     root            12 Jul  8 14:45 file3 -> ..data/file3

#kubectl exec dapi-test-pod -- cat /etc/config/file1

Hi i'm file1 !!!

#kubectl exec dapi-test-pod -- cat /etc/config/file3

Hi i'm file3
;))))!!!!

[sbezverk]

@vefimova I will redo this test and let you know the result, hopefully it was just a mistake on my side. Thank you.

[yadzhang]

Can K8S provide an option for updating or not updating the configuration in the container while it's running? If we update configmap, but do not want to spread the configuration to all conatainers. K8S can provide an option when create app.

[tobilarscheid]

Hi,

I can't reproduce the bug as well. I did however come here by googling the issue, simply for the reason that updating the file in the container takes a few seconds after the config map has been updated. So just leaving this here in case someone ends up here as well!

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