executor: set CpuWeight in cgroup-v2 (#11287)

Cgroup-v2 uses `cpu.weight` property instead of cpu shares: https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html#cpu-interface-files . And it uses a different range (i.e. `[1, 10000]`) from cpu.shares (i.e. `[2, 262144]`) to make things more interesting. Luckily, the libcontainer provides a helper function to perform the conversion [`ConvertCPUSharesToCgroupV2Value`](https://pkg.go.dev/github.com/opencontainers/[email protected]/libcontainer/cgroups#ConvertCPUSharesToCgroupV2Value). I have confirmed that docker/libcontainer performs the conversion as well in https://github.com/opencontainers/runc/blob/v1.0.2/libcontainer/specconv/spec_linux.go#L536-L541 , and that CpuShares is ignored by libcontainer in https://github.com/opencontainers/runc/blob/v1.0.2/libcontainer/cgroups/fs2/cpu.go#L24-L29 .
hashicorp · Oct 14, 2021 · feb450a · feb450a
1 parent c0a1d3a
commit feb450a
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diff --git a/.changelog/11287.txt b/.changelog/11287.txt
@@ -0,0 +1,4 @@
+
+```release-note:bug
+driver/exec: Set CPU resource limits when cgroup-v2 is enabled
+```
diff --git a/drivers/shared/executor/executor_linux.go b/drivers/shared/executor/executor_linux.go
@@ -697,8 +697,9 @@ func configureCgroups(cfg *lconfigs.Config, command *ExecCommand) error {
 		return fmt.Errorf("resources.Cpu.CpuShares must be equal to or greater than 2: %v", cpuShares)
 	}
 
-	// Set the relative CPU shares for this cgroup.
+	// Set the relative CPU shares for this cgroup, and convert for cgroupv2
 	cfg.Cgroups.Resources.CpuShares = uint64(cpuShares)
+	cfg.Cgroups.Resources.CpuWeight = cgroups.ConvertCPUSharesToCgroupV2Value(uint64(cpuShares))
 
 	if command.Resources.LinuxResources != nil && command.Resources.LinuxResources.CpusetCgroupPath != "" {
 		cfg.Hooks = lconfigs.Hooks{