open-nomad/client/fingerprint/cgroup.go

91 lines
2.6 KiB
Go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0
package fingerprint
import (
"time"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/nomad/client/lib/cgutil"
)
const (
cgroupUnavailable = "unavailable" // "available" is over in cgroup_linux
cgroupMountPointAttribute = "unique.cgroup.mountpoint"
cgroupVersionAttribute = "unique.cgroup.version"
cgroupDetectInterval = 15 * time.Second
)
type CGroupFingerprint struct {
logger hclog.Logger
lastState string
mountPointDetector MountPointDetector
versionDetector CgroupVersionDetector
}
// MountPointDetector isolates calls to the cgroup library.
//
// This facilitates testing where we can implement fake mount points to test
// various code paths.
type MountPointDetector interface {
// MountPoint returns a cgroup mount-point.
//
// In v1, this is one arbitrary subsystem (e.g. /sys/fs/cgroup/cpu).
//
// In v2, this is the actual root mount point (i.e. /sys/fs/cgroup).
MountPoint() (string, error)
}
// DefaultMountPointDetector implements the interface detector which calls the cgroups
// library directly
type DefaultMountPointDetector struct {
}
// MountPoint calls out to the default cgroup library.
func (*DefaultMountPointDetector) MountPoint() (string, error) {
return cgutil.FindCgroupMountpointDir()
}
// CgroupVersionDetector isolates calls to the cgroup library.
type CgroupVersionDetector interface {
// CgroupVersion returns v1 or v2 depending on the cgroups version in use.
CgroupVersion() string
}
// DefaultCgroupVersionDetector implements the version detector which calls the
// cgroups library directly.
type DefaultCgroupVersionDetector struct {
}
func (*DefaultCgroupVersionDetector) CgroupVersion() string {
if cgutil.UseV2 {
return "v2"
}
return "v1"
}
// NewCGroupFingerprint returns a new cgroup fingerprinter
func NewCGroupFingerprint(logger hclog.Logger) Fingerprint {
return &CGroupFingerprint{
logger: logger.Named("cgroup"),
lastState: cgroupUnavailable,
mountPointDetector: new(DefaultMountPointDetector),
versionDetector: new(DefaultCgroupVersionDetector),
}
}
// clearCGroupAttributes clears any node attributes related to cgroups that might
// have been set in a previous fingerprint run.
func (f *CGroupFingerprint) clearCGroupAttributes(r *FingerprintResponse) {
r.RemoveAttribute(cgroupMountPointAttribute)
r.RemoveAttribute(cgroupVersionAttribute)
}
// Periodic determines the interval at which the periodic fingerprinter will run.
func (f *CGroupFingerprint) Periodic() (bool, time.Duration) {
return true, cgroupDetectInterval
}