docker

Documentation

Index

• Constants
• Variables
• func ContainerIDForPID(pid int) (string, error)
• func GetHostname() (string, error)
• func ScrapeAllCgroups() (map[string]*ContainerCgroup, error)
• type CgroupIOStat
• type CgroupMemStat
• type CgroupTimesStat
• type ContainerCgroup
  • func (c ContainerCgroup) CPU() (*CgroupTimesStat, error)
  • func (c ContainerCgroup) CPULimit() (float64, error)
  • func (c ContainerCgroup) CPUNrThrottled() (uint64, error)
  • func (c ContainerCgroup) ContainerStartTime() (int64, error)
  • func (c ContainerCgroup) IO() (*CgroupIOStat, error)
  • func (c ContainerCgroup) Mem() (*CgroupMemStat, error)
  • func (c ContainerCgroup) MemLimit() (uint64, error)
  • func (c ContainerCgroup) ParseSingleStat(target, file string) (uint64, error)

Constants

const NanoToUserHZDivisor float64 = 1e9 / 100

NanoToUserHZDivisor holds the divisor to convert cpu.usage to the same unit as cpu.system (USER_HZ = 1/100) TODO: get USER_HZ from gopsutil? Needs to patch it

Variables

var (
	// ErrDockerNotAvailable is returned if Docker is not running on the current machine.
	// We'll use this when configuring the DockerUtil so we don't error on non-docker machines.
	ErrDockerNotAvailable = errors.New("docker not available")

	// ErrDockerNotCompiled is returned if docker support is not compiled in.
	// User classes should handle that case as gracefully as possible.
	ErrDockerNotCompiled = errors.New("docker support not compiled in")
)

var (

	// ErrMissingTarget is an error set when a cgroup target is missing.
	ErrMissingTarget = errors.New("Missing cgroup target")
)

var ErrNotImplemented = errors.New("not implemented yet")

ErrNotImplemented is the "not implemented" error given by `gopsutil` when an OS doesn't support and API. Unfortunately it's in an internal package so we can't import it so we'll copy it here.

Functions

func ContainerIDForPID

func ContainerIDForPID(pid int) (string, error)

ContainerIDForPID is a lighter version of CgroupsForPids to only retrieve the container ID for origin detection. Returns container id as a string, empty if the PID is not in a container.

func GetHostname

func GetHostname() (string, error)

GetHostname returns the Docker hostname.

func ScrapeAllCgroups

func ScrapeAllCgroups() (map[string]*ContainerCgroup, error)

ScrapeAllCgroups returns ContainerCgroup for every container that's in a Cgroup. This version iterates on /{host/}proc to retrieve processes out of the namespace. We return as a map[containerID]Cgroup for easy look-up.

Types

type CgroupIOStat

type CgroupIOStat struct {
	ContainerID string
	ReadBytes   uint64
	WriteBytes  uint64
}

CgroupIOStat store I/O statistics about a cgroup.

type CgroupMemStat

type CgroupMemStat struct {
	ContainerID             string
	Cache                   uint64
	Swap                    uint64 // See SwapPresent to make sure it's a real zero
	SwapPresent             bool
	RSS                     uint64
	RSSHuge                 uint64
	MappedFile              uint64
	Pgpgin                  uint64
	Pgpgout                 uint64
	Pgfault                 uint64
	Pgmajfault              uint64
	InactiveAnon            uint64
	ActiveAnon              uint64
	InactiveFile            uint64
	ActiveFile              uint64
	Unevictable             uint64
	HierarchicalMemoryLimit uint64
	HierarchicalMemSWLimit  uint64 // One can safely assume 0 == absent
	TotalCache              uint64
	TotalRSS                uint64
	TotalRSSHuge            uint64
	TotalMappedFile         uint64
	TotalPgpgIn             uint64
	TotalPgpgOut            uint64
	TotalPgFault            uint64
	TotalPgMajFault         uint64
	TotalInactiveAnon       uint64
	TotalActiveAnon         uint64
	TotalInactiveFile       uint64
	TotalActiveFile         uint64
	TotalUnevictable        uint64
	MemUsageInBytes         uint64
	MemFailCnt              uint64
}

CgroupMemStat stores memory statistics about a cgroup.

type CgroupTimesStat

type CgroupTimesStat struct {
	ContainerID string
	System      uint64
	User        uint64
	UsageTotal  float64
}

CgroupTimesStat stores CPU times for a cgroup. Unit is userspace scheduling unit (USER_HZ, usually 1/100)

type ContainerCgroup

type ContainerCgroup struct {
	ContainerID string
	Pids        []int32
	Paths       map[string]string
	Mounts      map[string]string
}

ContainerCgroup is a structure that stores paths and mounts for a cgroup. It provides several methods for collecting stats about the cgroup using the paths and mounts metadata.

func (ContainerCgroup) CPU

func (c ContainerCgroup) CPU() (*CgroupTimesStat, error)

CPU returns the CPU status for this cgroup instance If the cgroup file does not exist then we just log debug return nothing.

func (ContainerCgroup) CPULimit

func (c ContainerCgroup) CPULimit() (float64, error)

CPULimit would show CPU limit for this cgroup. It does so by checking the cpu period and cpu quota config if a user does this:

docker run --cpus='0.5' ubuntu:latest

we should return 50% for that container If the limits files aren't available (on older version) then we'll return the default value of 100.

func (ContainerCgroup) CPUNrThrottled

func (c ContainerCgroup) CPUNrThrottled() (uint64, error)

CPUNrThrottled returns the number of times the cgroup has been throttle/limited because of CPU quota / limit If the cgroup file does not exist then we just log debug and return 0.

func (ContainerCgroup) ContainerStartTime

func (c ContainerCgroup) ContainerStartTime() (int64, error)

ContainerStartTime gets the stat for cgroup directory and use the mtime for that dir to determine the start time for the container this should work because the cgroup dir for the container would be created only when it's started

func (ContainerCgroup) IO

func (c ContainerCgroup) IO() (*CgroupIOStat, error)

IO returns the disk read and write bytes stats for this cgroup. Format:

8:0 Read 49225728 8:0 Write 9850880 8:0 Sync 0 8:0 Async 59076608 8:0 Total 59076608 252:0 Read 49094656 252:0 Write 9850880 252:0 Sync 0 252:0 Async 58945536 252:0 Total 58945536

func (ContainerCgroup) Mem

func (c ContainerCgroup) Mem() (*CgroupMemStat, error)

Mem returns the memory statistics for a Cgroup. If the cgroup file is not availble then we return an empty stats file.

func (ContainerCgroup) MemLimit

func (c ContainerCgroup) MemLimit() (uint64, error)

MemLimit returns the memory limit of the cgroup, if it exists. If the file does not exist or there is no limit then this will default to 0.

func (ContainerCgroup) ParseSingleStat

func (c ContainerCgroup) ParseSingleStat(target, file string) (uint64, error)

ParseSingleStat reads and converts a single-value cgroup stat file content to uint64.