The Kubernetes kubelet creates checkpoints which consists of metadata (checkpointed.pods)
and tar archives containing the actual pod checkpoints.
With the help of this tool, checkpointctl, it is possible to display, extract or insert
checkpoints.
To display the checkpoints which are currently in the kubelet's default checkpoint directory
just use checkpointctl show:
$ checkpointctl show
Displaying data from /var/lib/kubelet/checkpoints/checkpointed.pods
+-----------+-----------+-----------+-----------------------------------+---------------+
| POD | NAMESPACE | CONTAINER | IMAGE | ARCHIVE FOUND |
+-----------+-----------+-----------+-----------------------------------+---------------+
| my-redis | default | redis | redis | true |
+-----------+ +-----------+-----------------------------------+ +
| counters | | counter | quay.io/adrianreber/counter | |
+ + +-----------+-----------------------------------+ +
| | | wildfly | quay.io/adrianreber/wildfly-hello | |
+-----------+-----------+-----------+-----------------------------------+---------------+To extract all checkpoints from the kubelet use:
$ checkpointctl extract -o /tmp/checkpoints.tar
Extracting checkpoint data from /var/lib/kubelet/checkpoints/checkpointed.podsResulting in a tar archive at /tmp/checkpoints.tar which can then be used to insert
this checkpoint archive into another kubelet:
$ checkpointctl insert -i /tmp/checkpoints.tarInserting a checkpoint archive will add the new checkpoints to existing checkpoints.
All operations default to /var/lib/kubelet/checkpoints which can be changed using
the --target parameter.
The command checkpointctl show can also be used on an exported tar archive to see
which checkpoints are part of an exported tar archive:
$ checkpointctl show --target /tmp/checkpoints.tarWhile bug fixes can first be identified via an "issue", that is not required. It's ok to just open up a PR with the fix, but make sure you include the same information you would have included in an issue - like how to reproduce it.
PRs for new features should include some background on what use cases the new code is trying to address. When possible and when it makes sense, try to break-up larger PRs into smaller ones - it's easier to review smaller code changes. But only if those smaller ones make sense as stand-alone PRs.
Regardless of the type of PR, all PRs should include:
- well documented code changes;
- additional testcases: ideally, they should fail w/o your code change applied;
- documentation changes.
Squash your commits into logical pieces of work that might want to be reviewed separate from the rest of the PRs. Ideally, each commit should implement a single idea, and the PR branch should pass the tests at every commit. GitHub makes it easy to review the cumulative effect of many commits; so, when in doubt, use smaller commits.
PRs that fix issues should include a reference like Closes #XXXX in the
commit message so that github will automatically close the referenced issue
when the PR is merged.
Contributors must assert that they are in compliance with the Developer Certificate of Origin 1.1. This is achieved by adding a "Signed-off-by" line containing the contributor's name and e-mail to every commit message. Your signature certifies that you wrote the patch or otherwise have the right to pass it on as an open-source patch.
Unless mentioned otherwise in a specific file's header, all code in this project is released under the Apache 2.0 license.
The author of a change remains the copyright holder of their code (no copyright assignment). The list of authors and contributors can be retrieved from the git commit history and in some cases, the file headers.