Automatic merge from submit-queue
Expose SummaryProvider for reuse by other parts of kubelet
To support out of resource killing in the kubelet, we will introduce a new top-level module that will ensure node stability by checking if eviction thresholds have been met for memory and file-system usage on the node. In addition, it will then need information about pod memory and disk usage in order to make an eviction selection. Currently, this information is collected in `SummaryProvider` but it's hidden away and not available for re-use by other top-level modules of the kubelet. This initial refactor adds the ability to get summary stat information from the `ResourceAnalyzer` so it can be reused by other top-level modules.
I suspect we will further re-factor this area as code evolves, but this unblocks further progress on out-of-resource killing.
/cc @vishh @timothysc @kubernetes/sig-node @kubernetes/rh-cluster-infra
Automatic merge from submit-queue
Add memory available to summary stats provider
To support out of resource killing when low on memory, we want to let operators specify eviction thresholds based on available memory instead of memory usage for ease of use when working with heterogeneous nodes.
So for example, a valid eviction threshold would be the following:
* If node.memory.available < 200Mi for 30s, then evict pod(s)
For the node, `memory.availableBytes` is always known since the `memory.limit_in_bytes` is always known for root cgroup. For individual containers in pods, we only populate the `availableBytes` if the container was launched with a memory limit specified. When no memory limit is specified, the cgroupfs sets a value of 1 << 63 in the `memory.limit_in_bytes` so we look for a similar max value to handle unbounded limits, and ignore setting `memory.availableBytes`.
FYI @vishh @timstclair - as discussed on Slack.
/cc @kubernetes/sig-node @kubernetes/rh-cluster-infra
`--kubelet-cgroups` and `--system-cgroups` respectively.
Updated `--runtime-container` to `--runtime-cgroups`.
Cleaned up most of the kubelet code that consumes these flags to match
the flag name changes.
Signed-off-by: Vishnu kannan <vishnuk@google.com>
* Metrics will not be expose until they are hooked up to a handler
* Metrics are not cached and expose a dos vector, this must be fixed before release or the stats should not be exposed through an api endpoint
Add a `/stats/summary` endpoint to the kubelet which will return an
empty Summary{} struct (json formatted), as a summary API
placeholder. Once the next cAdvisor release is vendored, the summary
API will be filled in.
Changes include:
- Moving stats serving & routes to pkg/kubelet/server/stats/handler.go
- Managing the routes with restful.WebService, rather than manual
parsing
- Misc cleanup
These changes will make adding the new routes for /stats/summary more
manageable.
- Sample is now the toplevel struct, so all child structs have the same
timestamp
- Removed FilesystemStats. There are more discussions needed
wrt. volumes and disk accounting, so this will be added in a follow
up PR
- Removed Options. The most recent sample will be returned.
This API has been discussed ad nauseam across several forums, and this
API represents the latest conclusion. In summary, we will provide this
API as temporary solution for providing the new stats required for 1.2.
In the longterm this API will be split into "essential" stats, which
will be provided by a first-party API served through the kubelet, and
"non-essential" (monitoring) stats, which will be provided by a 3rd
party API served from a pod.
