kubelet: add --runonce flag #1534

proppy · 2014-10-02T00:39:48Z

Usage

kubelet --runonce --config some/pod-manifest.json

Description

The kubelet runs the pod specified by the manifest and exits when the containers are running.

This is useful for being able to bootstrap a kubelet pod with the kubelet binary.

Assuming the above is true, is there a race where sometimes the kubelet only starts locally configured pods, and other times, it manages to be noticed by the apiserver, get apiserver-managed pods scheduled on it, and then start those pods too? If so, that seems like it could cause problems, or at least be surprising.

If it works for your use case, I wonder if it makes sense to only start containers from a local manifest when kubelet is run with --runonce.

erictune · 2014-10-02T21:41:38Z

pkg/kubelet/runonce.go

+	if kl.dockerPuller == nil {
+		kl.dockerPuller = dockertools.NewDockerPuller(kl.dockerClient, kl.pullQPS, kl.pullBurst)
+	}
+	if kl.healthChecker == nil {


why health check if kubelet is going to exit soon? Seems like it just leads to unpredicable behavior for --runonce.

erictune · 2014-10-02T21:45:19Z

Looks good aside from previous comments.

proppy · 2014-10-02T22:02:46Z

I'm assuming you are want to use kubelet with --runonce as part of the boot process for a machine, to for example start cadvisor from a local manifest file? Is that right?

@erictune Yes, I updated the description to reflect this.

proppy · 2014-10-02T22:04:01Z

Assuming the above is true, is there a race where sometimes the kubelet only starts locally configured pods, and other times, it manages to be noticed by the apiserver, get apiserver-managed pods scheduled on it, and then start those pods too? If so, that seems like it could cause problems, or at least be surprising.

The changes in cmd/kubelet.go should disable etcd watching w/ --noonce. See: https://github.com/GoogleCloudPlatform/kubernetes/pull/1534/files#diff-a9f93108ac59ff44885fc0aea2f29e71R112

proppy · 2014-10-02T22:06:11Z

If it works for your use case, I wonder if it makes sense to only start containers from a local manifest when kubelet is run with --runonce.

Currently it only poll local file and/or an url, update the documentation to be more explicit.

erictune · 2014-10-02T22:17:54Z

LGTM

proppy · 2014-10-02T22:21:34Z

@erictune Thanks, I do want to add more tests before merging.

bgrant0607 · 2014-10-02T22:36:51Z

@proppy Please squash your commits when you're done, also.

proppy · 2014-10-02T22:39:39Z

@bgrant0607, will do I like keeping them that way during review, as it helps to review how the comments were addressed

thockin · 2014-10-02T23:58:01Z

please hold this PR until I can review, ETA tonight or tomorrow.

On Thu, Oct 2, 2014 at 3:39 PM, Johan Euphrosine notifications@github.com
wrote:

@bgrant0607 https://github.com/bgrant0607, will do I like keeping them
that way during review, as it helps to review how the comments were
addressed

Reply to this email directly or view it on GitHub
#1534 (comment)
.

thockin · 2014-10-03T17:38:35Z

cmd/kubelet/kubelet.go

@@ -63,6 +63,7 @@ var (
 	allowPrivileged    = flag.Bool("allow_privileged", false, "If true, allow containers to request privileged mode. [default=false]")
 	registryPullQPS    = flag.Float64("registry_qps", 0.0, "If > 0, limit registry pull QPS to this value.  If 0, unlimited. [default=0.0]")
 	registryBurst      = flag.Int("registry_burst", 10, "Maximum size of a bursty pulls, temporarily allows pulls to burst to this number, while still not exceeding registry_qps.  Only used if --registry_qps > 0")
+	runonce            = flag.Bool("runonce", false, "If true, exit after spawning pod from local manifests or remote urls. Exclusive with --etcd_servers and --enable-server")


s/pod/pods/

thockin · 2014-10-03T17:44:36Z

feedback done, hold removed (though now there is feedback)

On Thu, Oct 2, 2014 at 4:57 PM, Tim Hockin thockin@google.com wrote:

please hold this PR until I can review, ETA tonight or tomorrow.

On Thu, Oct 2, 2014 at 3:39 PM, Johan Euphrosine <notifications@github.com

wrote:

@bgrant0607 https://github.com/bgrant0607, will do I like keeping them
that way during review, as it helps to review how the comments were
addressed

Reply to this email directly or view it on GitHub
#1534 (comment)
.

proppy · 2014-10-03T18:22:12Z

rebased

proppy · 2014-10-04T00:57:32Z

Added basic tests and rebased, PTAL

thockin · 2014-10-04T03:29:15Z

LGTM

thockin · 2014-10-04T03:29:25Z

ok to merge in-hours

kubelet: add --runonce flag

bgrant0607 self-assigned this Oct 2, 2014

brendandburns closed this Oct 2, 2014

brendandburns reopened this Oct 2, 2014

bgrant0607 assigned erictune and unassigned bgrant0607 Oct 2, 2014

bgrant0607 added the bootstrapping label Oct 2, 2014

erictune reviewed Oct 2, 2014
View reviewed changes

thockin reviewed Oct 3, 2014
View reviewed changes

proppy force-pushed the kubelet-noonce branch from 089427f to ffe0bc8 Compare October 3, 2014 18:22

proppy force-pushed the kubelet-noonce branch from b13ac41 to 36267fe Compare October 4, 2014 00:57

proppy force-pushed the kubelet-noonce branch from 36267fe to 53a2012 Compare October 4, 2014 00:59

proppy force-pushed the kubelet-noonce branch from 53a2012 to acf338f Compare October 4, 2014 01:01

proppy added 2 commits October 3, 2014 18:02

kubelet: add --runonce flag, exits after starting pod from the manifest

f91162c

kubelet: add basic test for runonce

fa1dcd0

proppy force-pushed the kubelet-noonce branch from acf338f to fa1dcd0 Compare October 4, 2014 01:02

bgrant0607 added a commit that referenced this pull request Oct 4, 2014

Merge pull request #1534 from proppy/kubelet-noonce

a0bb739

kubelet: add --runonce flag

bgrant0607 merged commit a0bb739 into kubernetes:master Oct 4, 2014

proppy mentioned this pull request Oct 7, 2014

Fix a problem with for loops, copy semantics and async routines. #1616

Merged

bgrant0607 mentioned this pull request Nov 26, 2014

Make it easy to run Kubernetes on top of the Kubelet (aka self-hosting) #246

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kubelet: add --runonce flag #1534

kubelet: add --runonce flag #1534

proppy commented Oct 2, 2014

brendandburns commented Oct 2, 2014

erictune Oct 2, 2014

proppy Oct 2, 2014

erictune commented Oct 2, 2014

erictune Oct 2, 2014

proppy Oct 2, 2014

erictune commented Oct 2, 2014

proppy commented Oct 2, 2014

proppy commented Oct 2, 2014

proppy commented Oct 2, 2014

erictune commented Oct 2, 2014

proppy commented Oct 2, 2014

bgrant0607 commented Oct 2, 2014

proppy commented Oct 2, 2014

thockin commented Oct 2, 2014

thockin Oct 3, 2014

proppy Oct 3, 2014

thockin commented Oct 3, 2014

proppy commented Oct 3, 2014

proppy commented Oct 4, 2014

thockin commented Oct 4, 2014

thockin commented Oct 4, 2014

+              	Err  error
+              }
+              // RunOnce poll from one configuratin update and run the associated pods.

kubelet: add --runonce flag #1534

kubelet: add --runonce flag #1534

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proppy commented Oct 2, 2014

Usage

Description

Related

TODO

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