Sysctl

With the osism.commons.sysctl role, it is possible to manage the attributes of the kernel via sysctl on a node.

The following defaults are set via the parameter sysctl_defaults.

Group	Attribute	Default
elasticsearch	vm.max_map_count	262144
rabbitmq	net.ipv4.tcp_keepalive_time	6
rabbitmq	net.ipv4.tcp_keepalive_intvl	3
rabbitmq	net.ipv4.tcp_keepalive_probes	3
rabbitmq	net.core.wmem_max	16777216
rabbitmq	net.core.rmem_max	16777216
rabbitmq	net.ipv4.tcp_fin_timeout	20
rabbitmq	net.ipv4.tcp_tw_reuse	1
rabbitmq	net.core.somaxconn	4096
rabbitmq	net.ipv4.tcp_syncookies	0
rabbitmq	net.ipv4.tcp_max_syn_backlog	8192
generic	vm.swappiness	1
compute	net.netfilter.nf_conntrack_max	1048576

The sysctl_extra parameter can be used to set your own parameters or overwrite existing parameters in the defaults.

Set attribute fs.inotify.max_user_instances to 256 for all nodes in group generic

sysctl_extra:
  generic:
    - name: fs.inotify.max_user_instances
      value: 256