containerd-config.toml - Man Page

The config.toml file is a configuration file for the containerd daemon. The file must be placed at /etc/containerd/config.toml or specified with the --config option of containerd to be used by the daemon. If the file does not exist at the appropriate location or is not provided via the --config option containerd uses its default configuration settings, which can be displayed with the containerd config(1) command.

The TOML file used to configure the containerd daemon settings has a short list of global settings followed by a series of sections for specific areas of daemon configuration. There is also a section for plugins that allows each containerd plugin to have an area for plugin-specific configuration and settings.

version

The version field in the config file specifies the config’s version. If no version number is specified inside the config file then it is assumed to be a version 1 config and parsed as such. Please use version = 2 to enable version 2 config as version 1 has been deprecated.

root

The root directory for containerd metadata. (Default: "/var/lib/containerd")

state

The state directory for containerd (Default: "/run/containerd")

plugin_dir

The directory for dynamic plugins to be stored

[grpc]

Section for gRPC socket listener settings. Contains the following properties:

• address (Default: "/run/containerd/containerd.sock")
• tcp_address
• tcp_tls_cert
• tcp_tls_key
• uid (Default: 0)
• gid (Default: 0)
• max_recv_message_size
• max_send_message_size

[ttrpc]

Section for TTRPC settings. Contains properties:

• address (Default: "")
• uid (Default: 0)
• gid (Default: 0)

[debug]

Section to enable and configure a debug socket listener. Contains four properties:

• address (Default: "/run/containerd/debug.sock")
• uid (Default: 0)
• gid (Default: 0)
• level (Default: "info") sets the debug log level. Supported levels are: "trace", "debug", "info", "warn", "error", "fatal", "panic"
• format (Default: "text") sets log format. Supported formats are "text" and "json"

[metrics]

Section to enable and configure a metrics listener. Contains two properties:

• address (Default: "") Metrics endpoint does not listen by default
• grpc_histogram (Default: false) Turn on or off gRPC histogram metrics

disabled_plugins

Disabled plugins are IDs of plugins to disable. Disabled plugins won't be initialized and started.

required_plugins

Required plugins are IDs of required plugins. Containerd exits if any required plugin doesn't exist or fails to be initialized or started.

[plugins]

The plugins section contains configuration options exposed from installed plugins. The following plugins are enabled by default and their settings are shown below. Plugins that are not enabled by default will provide their own configuration values documentation.

• [plugins."io.containerd.monitor.v1.cgroups"] has one option no_prometheus (Default: false)
• [plugins."io.containerd.service.v1.diff-service"] has one option default, a list by default set to ["walking"]

• [plugins."io.containerd.gc.v1.scheduler"] has several options that perform advanced tuning for the scheduler:

  • pause_threshold is the maximum amount of time GC should be scheduled (Default: 0.02),
  • deletion_threshold guarantees GC is scheduled after n number of deletions (Default: 0 [not triggered]),
  • mutation_threshold guarantees GC is scheduled after n number of database mutations (Default: 100),
  • schedule_delay defines the delay after trigger event before scheduling a GC (Default "0ms" [immediate]),
  • startup_delay defines the delay after startup before scheduling a GC (Default "100ms")

• [plugins."io.containerd.runtime.v2.task"] specifies options for configuring the runtime shim:

  • platforms specifies the list of supported platforms
  • sched_core Core scheduling is a feature that allows only trusted tasks to run concurrently on cpus sharing compute resources (eg: hyperthreads on a core). (Default: false)

• [plugins."io.containerd.service.v1.tasks-service"] has performance options:

  • blockio_config_file (Linux only) specifies path to blockio class definitions (Default: ""). Controls I/O scheduler priority and bandwidth throttling. See blockio configuration ⟨https://github.com/intel/goresctrl/blob/main/doc/blockio.md#configuration⟩ for details of the file format.
  • rdt_config_file (Linux only) specifies path to a configuration used for configuring RDT (Default: ""). Enables support for Intel RDT, a technology for cache and memory bandwidth management. See RDT configuration ⟨https://github.com/intel/goresctrl/blob/main/doc/rdt.md#configuration⟩ for details of the file format.

oom_score

The out of memory (OOM) score applied to the containerd daemon process (Default: 0)

[cgroup]

Section for Linux cgroup specific settings

• path (Default: "") Specify a custom cgroup path for created containers

[proxy_plugins]

Proxy plugins configures plugins which are communicated to over gRPC

• type (Default: "")
• address (Default: "")

timeouts

Timeouts specified as a duration

imports

Imports is a list of additional configuration files to include. This allows to split the main configuration file and keep some sections separately (for example vendors may keep a custom runtime configuration in a separate file without modifying the main config.toml). Imported files will overwrite simple fields like int or string (if not empty) and will append array and map fields. Imported files are also versioned, and the version can't be higher than the main config.

stream_processors

• accepts (Default: "[]") Accepts specific media-types
• returns (Default: "") Returns the media-type
• path (Default: "") Path or name of the binary
• args (Default: "[]") Args to the binary

The following is a complete config.toml default configuration example:

version = 2

root = "/var/lib/containerd"
state = "/run/containerd"
oom_score = 0
imports = ["/etc/containerd/runtime_*.toml", "./debug.toml"]

[grpc]
  address = "/run/containerd/containerd.sock"
  uid = 0
  gid = 0

[debug]
  address = "/run/containerd/debug.sock"
  uid = 0
  gid = 0
  level = "info"

[metrics]
  address = ""
  grpc_histogram = false

[cgroup]
  path = ""

[plugins]
  [plugins."io.containerd.monitor.v1.cgroups"]
    no_prometheus = false
  [plugins."io.containerd.service.v1.diff-service"]
    default = ["walking"]
  [plugins."io.containerd.gc.v1.scheduler"]
    pause_threshold = 0.02
    deletion_threshold = 0
    mutation_threshold = 100
    schedule_delay = 0
    startup_delay = "100ms"
  [plugins."io.containerd.runtime.v2.task"]
    platforms = ["linux/amd64"]
    sched_core = true
  [plugins."io.containerd.service.v1.tasks-service"]
    blockio_config_file = ""
    rdt_config_file = ""

Please file any specific issues that you encounter at https://github.com/containerd/containerd.

Phil Estes estesp@gmail.com ⟨mailto:estesp@gmail.com⟩

ctr(8), containerd-config(8), containerd(8)

containerd-config(8).