During operations such as "upgrade", kubeadm fetches the
ClusterConfiguration object from the kubeadm ConfigMap.
However, due to requiring node specifics it wraps it in an
InitConfiguration object. The function responsible for that is:
app/util/config#FetchInitConfigurationFromCluster().
A problem with this function (and sub-calls) is that it ignores
the static defaults applied from versioned types
(e.g. v1beta3/defaults.go) and only applies dynamic defaults for:
- API endpoints
- node registration
- etc...
The introduction of Init|JoinConfiguration.ImagePullPolicy now
has static defaulting of the NodeRegistration object with a default
policy of "PullIfNotPresent". Respect this defaulting by constructing
a defaulted internal InitConfiguration from
FetchInitConfigurationFromCluster() and only then apply the dynamic
defaults over it.
This fixes a bug where "kubeadm upgrade ..." fails when pulling images
due to an empty ("") ImagePullPolicy. We could assume that empty
string means default policy on runtime in:
cmd/kubeadm/app/preflight/checks.go#ImagePullCheck()
but that might actually not be the user intent during "init" and "join",
due to e.g. a typo. Similarly, we don't allow empty tokens
on runtime and error out.
* set `endpoints.kubernetes.io/over-capacity` to "truncated" when
number of addresses has been truncated to a 1000
* ready addresses are prioritized over non-ready addresses
* addresses are proportionally truncated across subsets
As of now, we allow PDBs to be applied to pods via
selectors, so there can be unmanaged pods(pods that
don't have backing controllers) but still have PDBs associated.
Such pods are to be logged instead of immediately throwing
a sync error. This ensures disruption controller is
not frequently updating the status subresource and thus
preventing excessive and expensive writes to etcd.
oomwatcher.NewWatcher returns "open /dev/kmsg: operation not permitted" error,
when running with sysctl value `kernel.dmesg_restrict=1`.
The error is negligible for KubeletInUserNamespace.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Errors during setting the following sysctl values are ignored:
- vm.overcommit_memory
- vm.panic_on_oom
- kernel.panic
- kernel.panic_on_oops
- kernel.keys.root_maxkeys
- kernel.keys.root_maxbytes
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
Enables support for running kubelet in a user namespace.
The user namespace has to be created before running kubelet.
All the node components such as CRI need to be running in the same user namespace.
See kubernetes/enhancements PR 1371 (merged) and issue 2033.
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
