- Call the auto-generated /healthz endpoint of our aggregated API server
- Use http for liveness even though tcp seems like it might be
more appropriate, because tcp probes cause TLS handshake errors
to appear in our logs every few seconds
- Use conservative timeouts and retries on the liveness probe to avoid
having our container get restarted when it is temporarily slow due
to running in an environment under resource pressure
- Use less conservative timeouts and retries for the readiness probe
to remove an unhealthy pod from the service less conservatively than
restarting the container
- Tuning the settings for retries and timeouts seem to be a mysterious
art, so these are just a first draft
- For high availability reasons, we would like our app to scale linearly
with the size of the control plane. Using a DaemonSet allows us to run
one pod on each node-role.kubernetes.io/master node.
- The hope is that the Service that we create should load balance
between these pods appropriately.
- Previously the golang code would create a Service and an APIService.
The APIService would be given an owner reference which pointed to
the namespace in which the app was installed.
- This prevented the app from being uninstalled. The namespace would
refuse to delete, so `kapp delete` or `kubectl delete` would fail.
- The new approach is to statically define the Service and an APIService
in the deployment.yaml, except for the caBundle of the APIService.
Then the golang code will perform an update to add the caBundle at
runtime.
- When the user uses `kapp deploy` or `kubectl apply` either tool will
notice that the caBundle is not declared in the yaml and will
therefore avoid editing that field.
- When the user uses `kapp delete` or `kubectl delete` either tool will
destroy the objects because they are statically declared with names
in the yaml, just like all of the other objects. There are no
ownerReferences used, so nothing should prevent the namespace from
being deleted.
- This approach also allows us to have less golang code to maintain.
- In the future, if our golang controllers want to dynamically add
an Ingress or other objects, they can still do that. An Ingress
would point to our statically defined Service as its backend.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
- Why? Because the discovery URL is already there in the kubeconfig; let's
not make our lives more complicated by passing it in via an env var.
- Also allow for ytt callers to not specify data.values.discovery_url - there
are going to be a non-trivial number of installers of placeholder-name
that want to use the server URL found in the cluster-info ConfigMap.
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
- Seems like the next step is to allow override of the CA bundle; I didn't
do that here for simplicity of the commit, but seems like it is the right
thing to do in the future.
This is a somewhat more basic way to get access to the certificate and private key we need to issue short lived certificates.
The host path, tolerations, and node selector here should work on any kubeadm-derived cluster including TKG-S and Kind.
Signed-off-by: Matt Moyer <moyerm@vmware.com>
Add initial aggregated API server (squashed from a bunch of commits).
Signed-off-by: Andrew Keesler <akeesler@vmware.com>
Signed-off-by: Aram Price <pricear@vmware.com>
Signed-off-by: Ryan Richard <richardry@vmware.com>
- Also fix mistakes in the deployment.yaml
- Also hardcode the ownerRef kind and version because otherwise we get an error
Signed-off-by: Monis Khan <mok@vmware.com>
