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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.

GroupAttributeDefault
elasticsearchvm.max_map_count262144
rabbitmqnet.ipv4.tcp_keepalive_time6
rabbitmqnet.ipv4.tcp_keepalive_intvl3
rabbitmqnet.ipv4.tcp_keepalive_probes3
rabbitmqnet.core.wmem_max16777216
rabbitmqnet.core.rmem_max16777216
rabbitmqnet.ipv4.tcp_fin_timeout20
rabbitmqnet.ipv4.tcp_tw_reuse1
rabbitmqnet.core.somaxconn4096
rabbitmqnet.ipv4.tcp_syncookies0
rabbitmqnet.ipv4.tcp_max_syn_backlog8192
genericvm.swappiness1
computenet.netfilter.nf_conntrack_max1048576

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