Writing to /etc/sysctl.conf

Pierre Ozoux

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Feb 23, 2015, 2:34:18 PM2/23/15

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Hi!

I just hit my first scalabilty issue, and I'm quiet happy 
https://microblog.pierre-o.fr/2015/hitting-my-first-scalling-issue-o---mysql-and-aio-max-nr

To solve this, I had to modify the value of fs.aio-max-nr

My question is, what is the best way in your opinion to persist this?
I think, I should write it with cloud-config, but it is just as a
confirmation that I'm asking you 

something like:
write_files:
  - path: /etc/sysctl.conf
    permissions: 0644
    owner: root
    content: |
      fs.aio-max-nr = 1048576

It is really just to know about best practive for this kind of matter,
like modifying kernel options.

Thanks for your help!

Pierre

Scott Laird

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Feb 23, 2015, 3:00:53 PM2/23/15

to Pierre Ozoux, coreo...@googlegroups.com

I'm doing something like this:

write_files:

- path: /etc/sysctl.d/baselayout.conf

content: |

net.ipv4.tcp_tw_recycle = 1

coreos:

units:

- name: systemd-sysctl.service

command: restart

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Alex Crawford

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Feb 23, 2015, 3:08:05 PM2/23/15

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Using write_files is the correct way. You should write into
/etc/sysctl.d/*.conf instead. You'll also need to re-evaluate the sysctl
config after it's been written.

#cloud-config
write_files:
- path: /etc/sysctl.d/aio-max.conf

permissions: 0644
owner: root
content: "fs.aio-max-nr = 1048576"

coreos:
units:
- name: systemd-sysctl.service
command: restart

-Alex

Michael Marineau

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Feb 23, 2015, 3:33:56 PM2/23/15

to Scott Laird, Pierre Ozoux, coreos-user

Note: the file /etc/sysctl.d/baselayout.conf will replace the defaults that we ship in /usr/lib/sysctl.d/baselayout.conf which may be your intent but just want that to be clear for anyone reading this thread.

Pierre Ozoux

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Feb 24, 2015, 9:23:15 AM2/24/15

to Michael Marineau, Scott Laird, coreos-user

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Thanks for your great help!
I'll update my blog post to make reference to this for CoreOS users.

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