The serviceAccountName is occasionally useful for clients running on
Kube that need to know who they are when talking to other components.
The nodeName is useful for PetSet or DaemonSet pods that need to make
calls back to the API to fetch info about their node.
Both fields are immutable, and cannot easily be retrieved in another
way.
This implements the proposal in:
docs/proposals/secret-configmap-downwarapi-file-mode.md
Fixes: #28317.
The mounttest image is updated so it returns the permissions of the linked file
and not the symlink itself.
Currently kubelet volume management works on the concept of desired
and actual world of states. The volume manager periodically compares the
two worlds and perform volume mount/unmount and/or attach/detach
operations. When kubelet restarts, the cache of those two worlds are
gone. Although desired world can be recovered through apiserver, actual
world can not be recovered which may cause some volumes cannot be cleaned
up if their information is deleted by apiserver. This change adds the
reconstruction of the actual world by reading the pod directories from
disk. The reconstructed volume information is added to both desired
world and actual world if it cannot be found in either world. The rest
logic would be as same as before, desired world populator may clean up
the volume entry if it is no longer in apiserver, and then volume
manager should invoke unmount to clean it up.
This fixes race conditions in configmap, secret, downwardapi & git_repo
volume plugins.
wrappedVolumeSpec vars used by volume mounters and unmounters contained
a pointer to api.Volume structs which were being patched by
NewWrapperMounter/NewWrapperUnmounter, causing race condition during
volume mounts.
Automatic merge from submit-queue
Remove an empty line being output when exposing annotations and labels via downward api volume
The issue is that formatMap function (for annotations and labels) in pkg/fieldpath/fieldpath.go appends a "\n" after each key value pair which is correct for all pairs except the last pair because then a complete string is returned with a "\n" in the end. It is inconsistent with other strings (metadata.name, namespace and resources) being returned as they dont have "\n" in the end. These returned strings are processed by sortLines function in pkg/volume/downwardapi/downwardapi.go and the function finally appends "\n" to each string, but incorrectly outputs an empty line if there is an already "\n" in the end with the input string. To illustrate:
The sortLines works as follows: lets say the input string is : "a\nb\nc\n".
1. It splits them as "a", "b", "c", "" (note empty string in the end).
2. it sort them: "", "a", b", "c"
3. And then it appends "\n" again to each string: "\n", "a\n" ,"b\n", "c\n"
So we can see that it is erroneously creating an empty string in the beginning when the input string to sortLines has "\n" in the end. As I said above, it is not an issue with metadata.name, namespace and resources as their input strings are without \n" in the end.
So now, the output in the downward api volume, (using the example in http://kubernetes.io/docs/user-guide/downward-api/):
```
# cat /etc/annotations
zone="us-est-coast"
cluster="test-cluster1"
rack="rack-22"
```
After this patch, the output will be correct and without the erroneous empty line in the beginning.
I could think other ways to solve this but I found the way in this patch with minimal code changes.
@kubernetes/rh-cluster-infra
This commit adds a new volume manager in kubelet that synchronizes
volume mount/unmount (and attach/detach, if attach/detach controller
is not enabled).
This eliminates the race conditions between the pod creation loop
and the orphaned volumes loops. It also removes the unmount/detach
from the `syncPod()` path so volume clean up never blocks the
`syncPod` loop.
- Add volume.MetricsProvider function to Volume interface.
- Add volume.MetricsDu for providing metrics via executing "du".
- Add volulme.MetricsNil for unsupported Volumes.
Rajat Ramesh Koujalagi