Index · Directives systemd 247

Name

oomd.conf, oomd.conf.d — Global systemd-oomd configuration files

Synopsis

/etc/systemd/oomd.conf

/etc/systemd/oomd.conf.d/*.conf

/usr/lib/systemd/oomd.conf.d/*.conf

Description

These files configure the various parameters of the systemd(1) userspace out-of-memory (OOM) killer, systemd-oomd.service(8). See systemd.syntax(7) for a general description of the syntax.

Configuration Directories and Precedence

The default configuration is defined during compilation, so a configuration file is only needed when it is necessary to deviate from those defaults. By default, the configuration file in /etc/systemd/ contains commented out entries showing the defaults as a guide to the administrator. This file can be edited to create local overrides.

When packages need to customize the configuration, they can install configuration snippets in /usr/lib/systemd/*.conf.d/ or /usr/local/lib/systemd/*.conf.d/. The main configuration file is read before any of the configuration directories, and has the lowest precedence; entries in a file in any configuration directory override entries in the single configuration file. Files in the *.conf.d/ configuration subdirectories are sorted by their filename in lexicographic order, regardless of in which of the subdirectories they reside. When multiple files specify the same option, for options which accept just a single value, the entry in the file with the lexicographically latest name takes precedence. For options which accept a list of values, entries are collected as they occur in files sorted lexicographically.

Files in /etc/ are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages. It is recommended to prefix all filenames in those subdirectories with a two-digit number and a dash, to simplify the ordering of the files.

To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null in the configuration directory in /etc/, with the same filename as the vendor configuration file.

[OOM] Section Options

The following options are available in the [OOM] section:

SwapUsedLimitPercent=

Sets the limit for swap usage on the system before systemd-oomd will take action. If the percentage of swap used on the system is more than what is defined here, systemd-oomd will act on eligible descendant cgroups, starting from the ones with the highest swap usage to the lowest swap usage. Which cgroups are monitored and what action gets taken depends on what the unit has configured for ManagedOOMSwap=. Takes a percentage value between 0% and 100%, inclusive. Defaults to 90%.

DefaultMemoryPressureLimitPercent=

Sets the limit for memory pressure on the unit's cgroup before systemd-oomd will take action. A unit can override this value with ManagedOOMMemoryPressureLimitPercent=. The memory pressure for this property represents the fraction of time in a 10 second window in which all tasks in the cgroup were delayed. For each monitored cgroup, if the memory pressure on that cgroup exceeds the limit set for more than 30 seconds, systemd-oomd will act on eligible descendant cgroups, starting from the ones with the most reclaim activity to the least reclaim activity. Which cgroups are monitored and what action gets taken depends on what the unit has configured for ManagedOOMMemoryPressure=. Takes a percentage value between 0% and 100%, inclusive. Defaults to 60%.

See Also

systemd(1), systemd.resource-control(5), systemd-oomd.service(8), oomctl(1)