Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Add proxy for container streaming in kubelet for streaming auth.
For https://github.com/kubernetes/kubernetes/issues/36666, option 2 of https://github.com/kubernetes/kubernetes/issues/36666#issuecomment-378440458.
This PR:
1. Removed the `DirectStreamingRuntime`, and changed `IndirectStreamingRuntime` to `StreamingRuntime`. All `DirectStreamingRuntime`s, `dockertools` and `rkt`, were removed.
2. Proxy container streaming in kubelet instead of returning redirect to apiserver. This solves the container runtime authentication issue, which is what we agreed on in https://github.com/kubernetes/kubernetes/issues/36666.
Please note that, this PR replaced the redirect with proxy directly instead of adding a knob to switch between the 2 behaviors. For existing CRI runtimes like containerd and cri-o, they should change to serve container streaming on localhost, so as to make the whole container streaming connection secure.
If a general authentication mechanism proposed in https://github.com/kubernetes/kubernetes/issues/62747 is ready, we can switch back to redirect, and all code can be found in github history.
Please also note that this added some overhead in kubelet when there are container streaming connections. However, the actual bottleneck is in the apiserver anyway, because it does proxy for all container streaming happens in the cluster. So it seems fine to get security and simplicity with this overhead. @derekwaynecarr @mrunalp Are you ok with this? Or do you prefer a knob?
@yujuhong @timstclair @dchen1107 @mikebrow @feiskyer
/cc @kubernetes/sig-node-pr-reviews
**Release note**:
```release-note
Kubelet now proxies container streaming between apiserver and container runtime. The connection between kubelet and apiserver is authenticated. Container runtime should change streaming server to serve on localhost, to make the connection between kubelet and container runtime local.
In this way, the whole container streaming connection is secure. To switch back to the old behavior, set `--redirect-container-streaming=true` flag.
```
Automatic merge from submit-queue (batch tested with PRs 61147, 62236, 62018). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
fix local volume absolute path issue on Windows
**What this PR does / why we need it**:
remove IsAbs validation on local volume since it does not work on windows cluster, Windows absolute path `D:` is not allowed in local volume, the [validation](https://github.com/kubernetes/kubernetes/blob/master/pkg/apis/core/validation/validation.go#L1386) happens on both master and agent node, while for windows cluster, the master is Linux and agent is Windows, so `path.IsAbs()` func will not work all in both nodes.
**Instead**, this PR use `MakeAbsolutePath` func to convert `local.path` value in kubelet, it supports both linux and windows styple.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#62016
**Special notes for your reviewer**:
**Release note**:
```
fix local volume absolute path issue on Windows
```
/sig storage
/sig windows
use MakeAbsolutePath to convert path in Windows
fix test error: allow relative path for local volume
fix comments
fix comments and add windows unit tests
We have 2 scenarios where we copy /etc/hosts
- with host network (we just copy the /etc/hosts from node)
- without host network (create a fresh /etc/hosts from pod info)
We are having trouble figuring out whether a /etc/hosts in a
pod/container has been "fixed-up" or not. And whether we used
host network or a fresh /etc/hosts in the various ways we start
up the tests which are:
- VM/box against a remote cluster
- As a container inside the k8s cluster
- DIND scenario in CI where test runs inside a managed container
Please see previous mis-guided attempt to fix this problem at
ba20e63446 In this commit we revert
the code from there as well.
So we should make sure:
- we always add a header if we touched the file
- we add slightly different headers so we can figure out if we used the
host network or not.
Update the test case to inject /etc/hosts from node to another path
(/etc/hosts-original) as well and use that to compare.
Users must not be allowed to step outside the volume with subPath.
Therefore the final subPath directory must be "locked" somehow
and checked if it's inside volume.
On Windows, we lock the directories. On Linux, we bind-mount the final
subPath into /var/lib/kubelet/pods/<uid>/volume-subpaths/<container name>/<subPathName>,
it can't be changed to symlink user once it's bind-mounted.
This also incorporates the version string into the package name so
that incompatibile versions will fail to connect.
Arbitrary choices:
- The proto3 package name is runtime.v1alpha2. The proto compiler
normally translates this to a go package of "runtime_v1alpha2", but
I renamed it to "v1alpha2" for consistency with existing packages.
- kubelet/apis/cri is used as "internalapi". I left it alone and put the
public "runtimeapi" in kubelet/apis/cri/runtime.
Since Mesos is no longer in your main repository and since we have
things like dynamic kubelet configuration in progress, we should
drop these undocumented, untested, private hooks.
cmd/kubelet/app/server.go::CreateAPIServerClientConfig
CreateAPIServerClientConfig::getRuntime
pkg/kubelet/kubelet_pods.go::getPhase
Also remove stuff from Dependencies struct that were specific to
the Mesos integration (ContainerRuntimeOptions and Options)
Also remove stale references in test/e2e and and test owners file
The POSIX standard restricts environment variable names to uppercase
letters, digits, and the underscore character in shell contexts only.
For generic application usage, it is stated that all other characters
shall be tolerated.
This change relaxes the rules to some degree. Namely, we stop requiring
environment variable names to be strict C_IDENTIFIERS and start
permitting lowercase, dot, and dash characters.
Public container images using environment variable names beyond the
shell-only context can benefit from this relaxation. Elasticsearch is
one popular example.
Introduced chages:
1. Re-writing of the resolv.conf file generated by docker.
Cluster dns settings aren't passed anymore to docker api in all cases, not only for pods with host network:
the resolver conf will be overwritten after infra-container creation to override docker's behaviour.
2. Added new one dnsPolicy - 'ClusterFirstWithHostNet', so now there are:
- ClusterFirstWithHostNet - use dns settings in all cases, i.e. with hostNet=true as well
- ClusterFirst - use dns settings unless hostNetwork is true
- Default
Fixes#17406
Automatic merge from submit-queue
Allow multipe DNS servers as comma-seperated argument for kubelet --dns
This PR explores how kubectls "--dns" could be extended to specify multiple DNS servers for in-cluster PODs. Testing on the local libvirt-coreos cluster shows that multiple DNS server are injected without issues.
Specifying multiple DNS servers increases resilience against
- Packet drops
- Single server failure
I am debugging services that do 50+ DNS requests for a single incoming interactive request, thus highly increase the chance of a slowdown (+5s) due to a single packet drop. Switching to two DNS servers will reduce the impact of the issues (roughly +1s on glibc, 0s on musl, error-rate goes down to error-rate^2).
Note that there is no need to change any runtime related code as far as I know. In the case of "default" dns the /etc/resolv.conf is parsed and multiple DNS server are send to the backend anyway. This only adds the same capability for the clusterFirst case.
I've heard from @thockin that multiple DNS entries are somehow considered. I've no idea what was considered, though. This is what I would like to see for our production use, though.
```release-note
NONE
```
- adjust ports to int32
- CRI flows the websocket ports as query params
- Do not validate ports since the protocol is unknown
SPDY flows the ports as headers and websockets uses query params
- Only flow query params if there is at least one port query param
Depending on an exact cluster setup multiple dns may make sense.
Comma-seperated lists of DNS server are quite common as DNS servers
are always plain IPs.
Automatic merge from submit-queue
Optional configmaps and secrets
Allow configmaps and secrets for environment variables and volume sources to be optional
Implements approved proposal c9f881b7bb
Release note:
```release-note
Volumes and environment variables populated from ConfigMap and Secret objects can now tolerate the named source object or specific keys being missing, by adding `optional: true` to the volume or environment variable source specifications.
```
Jordan Liggitt