Support for exposing PSI metrics #3083

dqminh · 2022-03-23T11:28:42Z

This depends on opencontainers/runc#3358, so it should not be merged as-is, but we can review the structure and how metrics are exposed.

k8s-ci-robot · 2022-03-23T11:28:51Z

Hi @dqminh. Thanks for your PR.

I'm waiting for a google member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Signed-off-by: Daniel Dao <dqminh89@gmail.com>

This adds 2 new set of metrics: - `psi_total`: read total number of seconds a resource is under pressure - `psi_avg`: read ratio of time a resource is under pressure over a sliding time window. For more details about these definitions, see: - https://www.kernel.org/doc/html/latest/accounting/psi.html - https://facebookmicrosites.github.io/psi/docs/overview Signed-off-by: Daniel Dao <dqminh89@gmail.com>

This adds support for reading PSI metrics via prometheus. We exposes the following for `psi_total`: ``` container_cpu_psi_total_seconds container_memory_psi_total_seconds container_io_psi_total_seconds ``` And for `psi_avg`: ``` container_cpu_psi_avg10_ratio container_cpu_psi_avg60_ratio container_cpu_psi_avg300_ratio container_memory_psi_avg10_ratio container_memory_psi_avg60_ratio container_memory_psi_avg300_ratio container_io_psi_avg10_ratio container_io_psi_avg60_ratio container_io_psi_avg300_ratio ``` Signed-off-by: Daniel Dao <dqminh89@gmail.com>

szuecs · 2022-11-04T19:01:35Z

@bobbypage does this need to wait longer, anything missing?
I ask because there is an internal request to support this feature. :)

@dqminh likely it needs a rebase, maybe you can do it :)

bobbypage · 2022-11-04T19:41:15Z

We are still waiting for opencontainers/runc#3358 to merged in runc...

szuecs · 2022-11-14T18:52:24Z

@bobbypage not sure should I take over the PR?
@dqminh thoughts?

Signed-off-by: liuqiming.lqm <liuqiming.lqm@alibaba-inc.com>

SuperQ · 2023-04-17T23:29:00Z

Fyi, it's unnecessary and not in best practices to expose the pre-computed averages in Prometheus.

Prometheus can compute arbitrary averages from the Total data.

nmlc · 2023-08-23T05:51:31Z

Any news here? Seems like runc PSI pr got merged

SuperQ · 2023-08-23T06:28:41Z

metrics/prometheus.go

+	if includedMetrics.Has(container.PSITotalMetrics) {
+		c.containerMetrics = append(c.containerMetrics, []containerMetric{
+			{
+				name:        "container_cpu_psi_total_seconds",


Suggested change

name: "container_cpu_psi_total_seconds",

name: "container_pressure_cpu_seconds_total",

SuperQ · 2023-08-23T06:29:17Z

metrics/prometheus.go

+					return getPSIValues(s, &s.Cpu.PSI, "total")
+				},
+			}, {
+				name:        "container_memory_psi_total_seconds",


Suggested change

name: "container_memory_psi_total_seconds",

name: "container_pressure_memory_seconds_total",

SuperQ · 2023-08-23T06:30:10Z

metrics/prometheus.go

+					return getPSIValues(s, &s.Memory.PSI, "total")
+				},
+			}, {
+				name:        "container_io_psi_total_seconds",


Suggested change

name: "container_io_psi_total_seconds",

name: "container_pressure_io_seconds_total",

SuperQ · 2023-08-23T06:31:58Z

metrics/prometheus.go

+	if includedMetrics.Has(container.PSIAvgMetrics) {
+		makePSIAvgMetric := func(controller, window string) containerMetric {
+			return containerMetric{
+				name:        fmt.Sprintf("container_%s_psi_avg%s_ratio", controller, window),
+				help:        fmt.Sprintf("Ratio of time spent under %s pressure over time window of %s seconds", controller, window),
+				valueType:   prometheus.GaugeValue,
+				extraLabels: []string{"kind"},
+				getValues: func(s *info.ContainerStats) metricValues {
+					switch controller {
+					case "cpu":
+						return getPSIValues(s, &s.Cpu.PSI, "avg"+window)
+					case "memory":
+						return getPSIValues(s, &s.Memory.PSI, "avg"+window)
+					case "io":
+						return getPSIValues(s, &s.DiskIo.PSI, "avg"+window)
+					default:
+						return nil
+					}
+				},
+			}
+		}
+		for _, controller := range []string{"cpu", "memory", "io"} {
+			for _, window := range []string{"10", "60", "300"} {
+				c.containerMetrics = append(c.containerMetrics, makePSIAvgMetric(controller, window))
+			}
+		}
+	}


These metrics are unnecessary in Prometheus as we can compute averages from the counters. Please remove them to avoid excess metric cardinality.

Suggested change

if includedMetrics.Has(container.PSIAvgMetrics) {

makePSIAvgMetric := func(controller, window string) containerMetric {

return containerMetric{

name: fmt.Sprintf("container_%s_psi_avg%s_ratio", controller, window),

help: fmt.Sprintf("Ratio of time spent under %s pressure over time window of %s seconds", controller, window),

valueType: prometheus.GaugeValue,

extraLabels: []string{"kind"},

getValues: func(s *info.ContainerStats) metricValues {

switch controller {

case "cpu":

return getPSIValues(s, &s.Cpu.PSI, "avg"+window)

case "memory":

return getPSIValues(s, &s.Memory.PSI, "avg"+window)

case "io":

return getPSIValues(s, &s.DiskIo.PSI, "avg"+window)

default:

return nil

}

},

}

}

for _, controller := range []string{"cpu", "memory", "io"} {

for _, window := range []string{"10", "60", "300"} {

c.containerMetrics = append(c.containerMetrics, makePSIAvgMetric(controller, window))

}

}

}

SuperQ · 2023-08-23T06:40:40Z

metrics/prometheus.go

+	case "total":
+		// total is measured as microseconds
+		v = append(v, metricValue{value: float64(time.Duration(psi.Some.Total)*time.Microsecond) / float64(time.Second), timestamp: s.Timestamp, labels: []string{"some"}})
+		v = append(v, metricValue{value: float64(time.Duration(psi.Full.Total)*time.Microsecond) / float64(time.Second), timestamp: s.Timestamp, labels: []string{"full"}})


Note for CPU, we don't need to expose "full". In practice, I've only found the "some" metrics to be useful. The "some" value is a superset of "full". IMO we should just include that to reduce the cardinality.

See the PSI docs:

CPU full is undefined at the system level, but has been reported since 5.13, so it is set to zero for backward compatibility.

I would like to raise my opinion for exposing "CPU full" metrics on a container(/cgroup) level.

While "CPU full" is undefined at the system level, it reports values for other cgroups:

$ cat /sys/fs/cgroup/user.slice/cpu.pressure some avg10=0.00 avg60=0.05 avg300=0.20 total=68139509 full avg10=0.00 avg60=0.00 avg300=0.00 total=40148380

Exposing both might be useful to differentiate between cgroups that try to execute more work than compute time available to them (indicated through "CPU some") and cgroups that are fully blocked/stalled (maybe because of other cgroups and/or process priority, …; indicated through "CPU full").

Interesting, thanks for this info. Are there kernel docs that document the per-cgroup behavior?

IMO this should be a separate metric name, rather than a label. The reason is that since some is a inclusive of full, doing something like sum(rate(container_pressure_cpu_seconds_total[1m])) would be confusing.

I would suggest these two metric names:

container_pressure_cpu_seconds_total

container_pressure_cpu_full_seconds_total

szuecs · 2023-10-31T09:14:58Z

@bobbypage can you set ok to test and do a review?
Would be great to see this in cadvisor

bobbypage · 2023-12-06T20:01:53Z

Waiting for new runc release to include opencontainers/runc@1aa7ca8

MathieuCesbron · 2024-02-23T17:24:25Z

Can we have an update on this ? I would like to access the psi interface. Thanks guys.

dims · 2024-02-23T17:36:18Z

@MathieuCesbron did you see the previous comment (the one before yours?)

dims · 2024-03-26T11:37:37Z

go.mod

 	google.golang.org/grpc v1.33.2
 	k8s.io/klog/v2 v2.4.0
 	k8s.io/utils v0.0.0-20211116205334-6203023598ed
 )
+
+replace github.com/opencontainers/runc => github.com/dqminh/runc v0.0.0-20220513155811-6414629ada8a


Please remove this and use the upstream runc as-is.

zouyee · 2024-04-07T03:19:48Z

runc has released 1.2.0-rc.1

zouyee · 2024-04-17T02:59:20Z

@bobbypage not sure should I take over the PR? @dqminh thoughts?

@szuecs take over ?

SuperQ · 2024-04-17T05:54:31Z

I would be happy to take over this change, I would like to make sure it aligns well with best practices. As it is, it does not.

szuecs · 2024-04-17T11:47:10Z

There is only a release candidate so I would wait until there's a proper release.
I don't mind that someone else would do it.

k8s-ci-robot added the needs-ok-to-test label Mar 23, 2022

dqminh force-pushed the psi branch 2 times, most recently from a870125 to 0a22793 Compare May 17, 2022 12:33

dqminh added 2 commits May 17, 2022 13:42

Replace runc with dqminh/runc for psi support

427f67e

Signed-off-by: Daniel Dao <dqminh89@gmail.com>

dqminh force-pushed the psi branch 3 times, most recently from 4c5c036 to 57ac945 Compare May 20, 2022 11:08

dqminh force-pushed the psi branch from 57ac945 to 5a27e49 Compare May 24, 2022 08:35

lukasmrtvy mentioned this pull request Oct 18, 2022

Podman support. #3021

Merged

john-liuqiming pushed a commit to cloud-native-observability/cadvisor that referenced this pull request Apr 4, 2023

merge PR google#3083

1883f03

Signed-off-by: liuqiming.lqm <liuqiming.lqm@alibaba-inc.com>

SuperQ suggested changes Aug 23, 2023

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dims reviewed Mar 26, 2024

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Support for exposing PSI metrics #3083

Support for exposing PSI metrics #3083

dqminh commented Mar 23, 2022

k8s-ci-robot commented Mar 23, 2022

szuecs commented Nov 4, 2022

bobbypage commented Nov 4, 2022

szuecs commented Nov 14, 2022

SuperQ commented Apr 17, 2023

nmlc commented Aug 23, 2023

SuperQ Aug 23, 2023

SuperQ Aug 23, 2023

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ein-stein-chen Oct 31, 2023 •

edited

SuperQ Oct 31, 2023

szuecs commented Oct 31, 2023

bobbypage commented Dec 6, 2023

MathieuCesbron commented Feb 23, 2024

dims commented Feb 23, 2024

dims Mar 26, 2024

zouyee commented Apr 7, 2024 •

edited

zouyee commented Apr 17, 2024

SuperQ commented Apr 17, 2024

szuecs commented Apr 17, 2024

	name: "container_cpu_psi_total_seconds",
	name: "container_pressure_cpu_seconds_total",

	name: "container_memory_psi_total_seconds",
	name: "container_pressure_memory_seconds_total",

	name: "container_io_psi_total_seconds",
	name: "container_pressure_io_seconds_total",

Support for exposing PSI metrics #3083

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Support for exposing PSI metrics #3083

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dqminh commented Mar 23, 2022

k8s-ci-robot commented Mar 23, 2022

szuecs commented Nov 4, 2022

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ein-stein-chen Oct 31, 2023 • edited

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zouyee commented Apr 7, 2024 • edited

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ein-stein-chen Oct 31, 2023 •

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edited