How to gather kernel parameters of remote hosts

Archives Ansible Project
1

How to i collect remote hosts kernel parameters using ansible. I’m looking to below type collect info of remote hosts . setup module doesn’t collect this info .

And sysctl module is to edit , can i use sysctl module just to list the parameters and not to modify anything ?

net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
net.ipv4.tcp_syncookies = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
fs.file-max = 209702
net.core.optmem_max = 10000000
net.core.rmem_default = 10000000
net.core.rmem_max = 10000000
net.core.wmem_default = 10000000
net.core.wmem_max = 10000000
net.ipv4.conf.all.rp_filter = 1
net.ipv4.tcp_max_tw_buckets = 2000000
net.ipv4.tcp_mem = 30000000 30000000 30000000
net.ipv4.tcp_rmem = 30000000 30000000 30000000
net.ipv4.tcp_wmem = 30000000 30000000 30000000
net.ipv4.ip_local_port_range = 32768 65000
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_fin_timeout = 30
net.ipv4.tcp_keepalive_time = 300
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_sack = 1
net.ipv4.igmp_max_memberships = 4096
kernel.pid_max = 131072
kernel.pid_max = 131072

Regards
Vikrant

2

Probably best done in one long cmd, for example:

  • hosts: all
    vars:
    params:
  • net.ipv4.ip_forward
  • net.ipv4.conf.default.rp_filter
  • net.ipv4.conf.default.accept_source_route
  • kernel.sysrq
  • kernel.core_uses_pid
  • net.ipv4.tcp_syncookies
  • kernel.msgmnb
  • kernel.msgmax
  • kernel.shmmax
  • kernel.shmall
  • fs.file-max
  • net.core.optmem_max
  • net.core.rmem_default
  • net.core.rmem_max
  • net.core.wmem_default
  • net.core.wmem_max
  • net.ipv4.conf.all.rp_filter
  • net.ipv4.tcp_max_tw_buckets
  • net.ipv4.tcp_mem
  • net.ipv4.tcp_rmem
  • net.ipv4.tcp_wmem
  • net.ipv4.ip_local_port_range
  • net.ipv4.ip_forward
  • net.ipv4.conf.default.rp_filter
  • net.ipv4.tcp_timestamps
  • net.ipv4.tcp_fin_timeout
  • net.ipv4.tcp_keepalive_time
  • net.ipv4.tcp_window_scaling
  • net.ipv4.tcp_sack
  • net.ipv4.igmp_max_memberships
  • kernel.pid_max
  • kernel.pid_max

tasks:

  • name: find out sysctl values
    shell: sysctl {{ params | join(’ ') }}
    register: sysctl_out

  • debug: var=sysctl_out

3

How to i collect remote hosts kernel parameters using ansible. I'm looking to below type collect info of remote hosts .
setup module doesn't collect this info .

And sysctl module is to edit , can i use sysctl module just to list the parameters and not to modify anything ?

According to its documentation, no.

But you can read the current values with

   command: sysctl -a
   register: sysctl_settings

Regards
        Racke

4

Optionally ask sysctl to print values only and set dictionary of the
parameters and values. For example

    - command: "sysctl -n {{ params | join(' ') }}"
      register: sysctl_out
    - set_fact:
        sysctl_dict: "{{ dict(params|zip(sysctl_out.stdout_lines)) }}"

HTH,

  -vlado