node/sdn: make /var/lib/cni persistent to ensure IPAM allocations stick around across node restart #13236
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…ck around across node restart With the move to a CNI plugin, docker no longer handles IPAM, but CNI does through openshift-sdn's usage of the 'host-local' CNI IPAM plugin. That plugin stores IPAM allocations under /var/lib/cni/. If the node container gets restarted, without presreving /var/lib/cni, the IPs currently allocated to running pods get lost and on restart, openshift-sdn may allocate those IPs to new pods causing duplicate allocations. This never happened with docker because it has its own persistent IPAM store that does not get removed when docker restarts. Also because (historically) when docker restarted, all the containers died and the IP allocations were released by the daemon. Fix this by ensuring that IPAM allocations (which are tied to the life of the pod, *not* the life of the openshift-node process) persist even if the openshift-node process restarts. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1427789
sdodson
approved these changes
Mar 3, 2017
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[merge] |
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continuous-integration/openshift-jenkins/merge SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pull_requests_origin_future/825/) (Base Commit: 4f89148) (Image: devenv-rhel7_6038) |
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Evaluated for origin merge up to ee0f0cc |
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[Test]ing while waiting on the merge queue |
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Evaluated for origin test up to ee0f0cc |
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continuous-integration/openshift-jenkins/test SUCCESS (https://ci.openshift.redhat.com/jenkins/job/test_pull_requests_origin_future/825/) (Base Commit: 4f89148) |
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With the move to a CNI plugin, docker no longer handles IPAM, but CNI does through
openshift-sdn's usage of the 'host-local' CNI IPAM plugin. That plugin stores
IPAM allocations under /var/lib/cni/.
If the node container gets restarted, without presreving /var/lib/cni, the IPs
currently allocated to running pods get lost and on restart, openshift-sdn
may allocate those IPs to new pods causing duplicate allocations.
This never happened with docker because it has its own persistent IPAM store that
does not get removed when docker restarts. Also because (historically) when docker
restarted, all the containers died and the IP allocations were released by the
daemon.
Fix this by ensuring that IPAM allocations (which are tied to the life of the pod,
not the life of the openshift-node process) persist even if the openshift-node
process restarts.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1427789
@sdodson @eparis @openshift/networking