The function TryRunCommand() uses an exponential backoff,
which is good, but it's inconsistent and only used in a couple
of places.
Remove its usage in the token.go#UpdateOrCreateTokens()
and switch to using the standard function used in other places -
PollUntilContextTimeout().
Remove wait.go#TryRunCommand(), as there are no other usages.
The function wait.go#WaitForKubeletAndFunc() has been used in
a number of places in kubeadm. It starts a go routine to wait for
the kubelet /healthz and in parallel starts another go routine
to wait for an custom function.
This logic is problematic. If kubeadm is waiting for the kubelet
in parallel with something that requires the kubelet, the right
solution would be to first wait for the kubelet in serial and only
then proceed with the other action. The parallelism here particularly
during "init" required a unwanted "initial timeout" of 40s, before
the kubelet waiting even starts. In most cases, this makes the kubelet
waiter to not even start, while the main point of waiting becomes
the "other action".
- Remove the function WaitForKubeletAndFunc() from the Waiter interface.
- Rename the function WaitForHealthyKubelet() to just WaitForKubelet()
to be consistent with the naming WaitForAPI().
- Update WaitForKubelet() to not use TryRunCommand() and instead
use PollUntilContextTimeout().
- Remove the "initial timeout" of 40s in WaitForKubelet().
- Make both WaitForKubelet() and WaitForAPI() use similar error
handling and output.
- Update all usage of WaitForKubelet() to be a serial call before
any other action, such as another wait* call.
- Make the default wait timeout for the kubelet
/healthz to be 1 minute (kubeadmconstants.DefaultKubeletTimeout).
- Apply updates to all implementations of the Waiter interface.
Explictly show the help msg that `kubeadm upgrade plan` can only run
on the node where "admin.conf" exists, normally, this is the control
plane node.
Signed-off-by: Dave Chen <dave.chen@arm.com>
27a68aee3a introduced context support for events. Creating an event
broadcaster with context makes tests more resilient against leaking goroutines
when that context gets canceled at the end of a test and enables per-test
output via ktesting.
To use this in kubelet, a more thorough code update is needed. For now,
context.TODO serves as a reminder that this is necessary.
The notes printed to the user from common.go when
loadConfig fails are outdated and incorrect.
If the config cannot be loaded the user should not be instructed
to re-upload the config with kubeadm commands. Instead they
should do it manually with kubectl.
On loadConfig() error just wrap the error in a simple message
and show it to the user.
The current setup stomps missing IsNotFound errors for Node objects.
The underlying fetching of init configuration uses
the node object to construct an initconfiguration for this
upgrade process, so if the Node is missing the kube-config CM
will be reported as missing, which is incorrect.
The component connection between kube-apiserver and kubelet does not
require the "O" field on the Subject to be set to the
"system:masters" privileged group. It can be a less
privileged group like "kubeadm:cluster-admins".
Change the group in the apiserve-kubelet-client
certificate specification. This cert is passed to
--kubelet-client-certificate.
kubemark's proxy mode exists to test how kube-proxy affects the load
on the apiserver, not how it affects the load on the node. There's no
need to generate fake iptables commands, because that all happens
entirely independently of the api watchers.
The addition of the "super-admin.conf" functionality required
init.go's Client() to create RBAC rules on its first creation.
However this created a problem with the "wait-control-plane" phase
of "kubeadm init" where a client is needed to connect to the
API server Discovery API's "/healthz" endpoint. The logic that ensures
the RBAC became the step where the API server wait was polled for.
To avoid this, introduce a new InitData function ClientWithoutBootstrap.
In "wait-control-plane" use this client, which has no permissions
(anonymous), but is sufficient to connect to the "/healthz".
Pending changes here would be:
- Stop using the "/healthz", instead a regular REST client from
the kubelet cert/key can be constructed.
- Make the wait for kubelet / API server linear (not in go routines).
This commit resolves an issue where certain KubeletConfig fields, specifically:
- FileCheckFrequency
- VolumeStatsAggPeriod
- EvictionPressureTransitionPeriod
- Authorization.Mode
- EvictionHard
were inadvertently overridden when not explicitly set in drop-in configs. To retain the
original values if they were absent in the drop-in configs, mergeKubeletConfigurations
uses a JSON patch merge strategy to selectively merge configurations. It prevents essential
configuration settings from being overridden, ensuring a more predictable behavior for users.
Signed-off-by: Sohan Kunkerkar <sohank2602@gmail.com>
Co-authored-by: Peter Hunt <pehunt@redhat.com>
