Kubeadm no longer supports kube-dns and CoreDNS is the only
supported DNS server. Remove ClusterConfiguration.DNS.Type
from v1beta3 that is used to set the DNS server type.
Originally raised as an issue with invalid versions to plan, but it has
been determined with air gapped environments and development versions it
is not possible to fully address that issue.
But one thing that was identified was that we can do a better job in how
we output the upgrade plan information. Kubeadm outputs the requested
version as "Latest stable version", though that may not actually be the
case. For this instance, we want to change this to "Target version" to
be a little more accurate.
Then in the component upgrade table that is emitted, the last column of
AVAILABLE isn't quite right either. Also changing this to TARGET to
reflect that this is the version we are targetting to upgrade to,
regardless of its availability.
There could be some improvements in checking available versions,
particularly in air gapped environments, to make sure we actually have
access to the requested version. But this at least clarifies some of the
output a bit.
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>
kubeadm uses image tags (such as `v3.4.3-0`) to specify the version of
etcd. However, the upgrade code in kubeadm uses the etcd client API to
fetch the currently deployed version. The result contains only the etcd
version without the additional information (such as image revision) that
is normally found in the tag. As a result it would refuse an upgrade
where the etcd versions match and the only difference is the image
revision number (`v3.4.3-0` to `v3.4.3-1`).
To fix the above issue, the following changes are done:
- Replace the existing etcd version querying code, that uses the etcd
client library, with code that returns the etcd image tag from the
local static pod manifest file.
- If an etcd `imageTag` is specified in the ClusterConfiguration during
upgrade, use that tag instead. This is done regardless if the tag was
specified in the configuration stored in the cluster or with a new
configuration supplied by the `--config` command line parameter.
If no custom tag is specified, kubeadm will select one depending on
the desired Kubernetes version.
- `kubeadm upgrade plan` no longer prints upgrade information about
external etcd. It's the user's responsibility to manage it in that
case.
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>
Some code in kubeadm was designed with the intent, that in the future CoreDNS
and kube-dns versions will match to specific K8s versions. This code is not
functional, since it does not perform any version matching. As of this moment,
no version matching is planned and a lot of boilerplate code is left useless.
The solution is simple - remove the unneeded parts to simplify the flow.
Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>
Currently kubeadm only performs an upgrade if the etcd cluster is
colocated with the control plane node. As this is only one possible
configuration, kubeadm should support upgrades with etcd clusters
that are not local to the node.
Signed-off-by: Craig Tracey <craigtracey@gmail.com>
- Test HasTLS()
- Instrument throughout upgrade plan and apply
- Update plan_test and apply_test to use new fake Cluster interfaces
- Add descriptions to upgrade range test
- Support KubernetesDir and EtcdDataDir in upgrade tests
- Cover etcdUpgrade in upgrade tests
- Cover upcoming TLSUpgrade in upgrade tests
