* Patch the node status instead of updating it.
Virtual-kubelet updates the node status periodically.
This change proposes we use the `Patch` API instead of `Update`,
to update the node status.
This avoids overwriting any node updates made by other controllers
in the system, for example a attach-detach controller.
Patch API does a strategic merge instead of overwriting
the entire object, which ensures parallel updates don't overwrite
each other.
Note: `PatchNodeStatus` reduces the time precision to the seconds-level
and therefore I corrected the test for this.
consider two controllers:
CONTROLLER 1 (virtual kubelet) | CONTROLLER 2
oldNode := nodes.Get(nodename) |
| node := nodes.Get(nodename)
| // update status with attached volumes info
| updateNode := Nodes.UpdateStatus(node)
// update vkubelet info on node status |
latestNode := Nodes.UpdateStatus(oldNode) |
<-- latestNode does not contain the volume info added by second controller.
with my patch change:
CONTROLLER 1 (virtual kubelet) | CONTROLLER 2
oldNode := Nodes.Get(nodename) |
| node := Nodes.Get(nodename)
| // update status with attached volumes info
| updateNode := Nodes.UpdateStatus(node)
node := oldNode.DeepCopy() |
// update vkubelet info on node status |
latestNode := util.PatchNodeStatus(oldNode, node) |
<-- latestNode contains the volume info added by second controller.
Testing Done: make test
* Introduce PatchNodeStatus into vkubelet.
* Pass only the node interface.
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