Currently, some circumstances may cause waitForDelete to
never succeed after the pod has been marked for deletion.
In particular, Nodes that are unresponsive and have
pods with local-storage will not be able to
successfully drain.
We should allow drain to ignore pods that have a
DeletionTimestamp older than a user-provided age.
This will allow controllers utilizing kubectl/drain
to optionally account for a pod that cannot be
removed due to a misbehaving node.
Kubernetes-commit: da53044abdf8c8a9771a5c3dfd861f0c4ec78c40
This commits allows specifying a context.Context
in the Helper type. This context is utilized to
cancel waitForDelete.
Kubernetes-commit: 8682e902f5487e04b893da7230125db0d7ae66b4
Currently, if eviction is supported during a drain operation,
eviction is always used.
This commit allows the user to specify disabling eviction.
This is particularly useful when you wish to ignore
PodDisruptionBudgets after a normal drain has failed for
some time.
Kubernetes-commit: 6c1d587d5142b95e6c169a198a086332a7e4d8ad
This patch removes pkg/util/mount completely, and replaces it with the
mount package now located at k8s.io/utils/mount. The code found at
k8s.io/utils/mount was moved there from pkg/util/mount, so the code is
identical, just no longer in-tree to k/k.
Kubernetes-commit: 0c5c3d8bb97d18a2a25977e92b3f7a49074c2ecb
And maybe the webhook authorizer cache.
This cache has two primary advantages over the LRU cache used currently:
- Cache hits don't acquire an exclusive lock.
- More importantly, performance doesn't fallover when the access pattern
scans a key space larger than an arbitrary size (e.g. the LRU
capacity).
The downside of using an expiring cache here is that it doesn't have a
maximum size so it's suspectible to DoS when the input is user
controlled. This is not the case for successful authentications, and
successful authentications have a natural expiry so it might be a good
fit here.
It has some a few differences compared to:
3d7318f29d/staging/src/k8s.io/client-go/tools/cache/expiration_cache.go
- Expiration is not entirely lazy so keys that are never accessed again
are still released from the cache.
- It does not acquire an exclusive lock on cache hits.
- It supports per entry ttls specified on Set.
The expiring cache (without striping) does somewhere in between the
simple cache and striped cache in the very contrived contention test
where every iteration acquires a write lock:
```
$ benchstat simple.log expiring.log
name old time/op new time/op delta
Cache-12 2.74µs ± 2% 2.02µs ± 3% -26.37% (p=0.000 n=9+9)
name old alloc/op new alloc/op delta
Cache-12 182B ± 0% 107B ± 4% -41.21% (p=0.000 n=8+9)
name old allocs/op new allocs/op delta
Cache-12 5.00 ± 0% 2.00 ± 0% -60.00% (p=0.000 n=10+10)
$ benchstat striped.log expiring.log
name old time/op new time/op delta
Cache-12 1.58µs ± 5% 2.02µs ± 3% +27.34% (p=0.000 n=10+9)
name old alloc/op new alloc/op delta
Cache-12 288B ± 0% 107B ± 4% -62.85% (p=0.000 n=10+9)
name old allocs/op new allocs/op delta
Cache-12 9.00 ± 0% 2.00 ± 0% -77.78% (p=0.000 n=10+10)
$ benchstat simple.log striped.log expiring.log
name \ time/op simple.log striped.log expiring.log
Cache-12 2.74µs ± 2% 1.58µs ± 5% 2.02µs ± 3%
name \ alloc/op simple.log striped.log expiring.log
Cache-12 182B ± 0% 288B ± 0% 107B ± 4%
name \ allocs/op simple.log striped.log expiring.log
Cache-12 5.00 ± 0% 9.00 ± 0% 2.00 ± 0%
```
I also naively replacemed the LRU cache with the expiring cache in the
more realisitc CachedTokenAuthenticator benchmarks:
https://gist.github.com/mikedanese/41192b6eb62106c0758a4f4885bdad53
For token counts that fit in the LRU, expiring cache does better because
it does not require acquiring an exclusive lock for cache hits.
For token counts that exceed the size of the LRU, the LRU has a massive
performance drop off. The LRU cache is around 5x slower (with lookups
taking 1 milisecond and throttled to max 40 lookups in flight).
```
$ benchstat before.log after.log
name old time/op new time/op delta
CachedTokenAuthenticator/tokens=100_threads=256-12 3.60µs ±22% 1.08µs ± 4% -69.91% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=500_threads=256-12 3.94µs ±19% 1.20µs ± 3% -69.57% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=2500_threads=256-12 3.07µs ± 6% 1.17µs ± 1% -61.87% (p=0.000 n=9+10)
CachedTokenAuthenticator/tokens=12500_threads=256-12 3.16µs ±17% 1.38µs ± 1% -56.23% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=62500_threads=256-12 15.0µs ± 1% 2.9µs ± 3% -80.71% (p=0.000 n=10+10)
name old alloc/op new alloc/op delta
CachedTokenAuthenticator/tokens=100_threads=256-12 337B ± 1% 300B ± 0% -11.06% (p=0.000 n=10+8)
CachedTokenAuthenticator/tokens=500_threads=256-12 307B ± 1% 304B ± 0% -0.96% (p=0.000 n=9+10)
CachedTokenAuthenticator/tokens=2500_threads=256-12 337B ± 1% 304B ± 0% -9.79% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=12500_threads=256-12 343B ± 1% 276B ± 0% -19.58% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=62500_threads=256-12 493B ± 0% 334B ± 0% -32.12% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
CachedTokenAuthenticator/tokens=100_threads=256-12 13.0 ± 0% 11.0 ± 0% -15.38% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=500_threads=256-12 12.0 ± 0% 11.0 ± 0% -8.33% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=2500_threads=256-12 13.0 ± 0% 11.0 ± 0% -15.38% (p=0.000 n=10+10)
CachedTokenAuthenticator/tokens=12500_threads=256-12 13.0 ± 0% 10.0 ± 0% -23.08% (p=0.000 n=9+10)
CachedTokenAuthenticator/tokens=62500_threads=256-12 17.0 ± 0% 12.0 ± 0% -29.41% (p=0.000 n=10+10)
```
Benchmarked with changes in #84423
Bugs: #83259#83375
Kubernetes-commit: 9167711fd18511ffc9c90ee306c462be9fc7999b
Arjun Naik