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# swith to sudo
sudo -i

# create swap
touch /2GiB.swap
chattr +C /2GiB.swap
fallocate -l 2048m /2GiB.swap
chmod 600 /2GiB.swap
mkswap /2GiB.swap

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Running Docker on two hosts, bridged with Open vSwitch

This Gist shows how to use Open vSwitch to bridge Docker containers on two hosts. It is based on this blog post http://goldmann.pl/blog/2014/01/21/connecting-docker-containers-on-multiple-hosts/.

A similar Gist using Tinc instead of Open vSwitch is available: https://gist.github.com/noteed/11031504.

Setup

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Running Docker on two hosts, bridged with Tinc

This Gist is similar to https://gist.github.com/noteed/8656989 which uses Open vSwitch instead of Tinc.

Setup

Download the install.sh script and run it:

> https://gist.githubusercontent.com/noteed/11031504/raw/install.sh

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#cloud-config

coreos:
  units:
    - name: systemd-sysctl.service
      command: restart
    - name: create-swap.service
      command: start
      runtime: true
      content: |

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Linux simple performance tweaks

Change the I/O Scheduler

Open $ vim /etc/default/grub then add elevator=noop next to GRUB_CMDLINE_LINUX_DEFAULT. Run $ update-grub and $ cat /sys/block/sda/queue/scheduler to be sure that noop is being used:

$ vim /etc/default/grub
$ update-grub
$ cat /sys/block/sda/queue/scheduler

[noop] deadline cfq

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# Configuration file for runtime kernel parameters.
# See sysctl.conf(5) for more information.

# See also http://www.nateware.com/linux-network-tuning-for-2013.html for
# an explanation about some of these parameters, and instructions for
# a few other tweaks outside this file.

# Protection from SYN flood attack.
net.ipv4.tcp_syncookies = 1

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# Model
from concurrency.fields import IntegerVersionField

class Image(models.Model):
    id = models.CharField(max_length=36, primary_key=True)
    human_id = models.CharField(max_length=255, null=True) # some images don't have human_id
    name = models.CharField(max_length=255)
    tenant_id = models.CharField(max_length=255, null=True) # some images don't have tenant_id
    version = IntegerVersionField() # django-concurrency

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global
  chroot  /var/lib/haproxy
  crt-base  /etc/pki/tls/certs
  daemon  
  group  haproxy
  log  127.0.0.1 local0
  maxconn  2000
  pidfile  /var/run/haproxy.pid
  stats  socket /var/lib/haproxy/stats
  tune.ssl.default-dh-param  2048

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upstream gitlab {
  server                    172.17.42.1:10080 fail_timeout=0;
}

# let gitlab deal with the redirection
server {
  listen                    80;
  server_name               git.example.com;
  server_tokens             off;
  root                      /dev/null;

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Make a directory to install CentOS 7.2.1511 in

[root@localhost ~]# mkdir /centos_chroot

Make a directory for the rpm database

[root@localhost ~]# mkdir -p /centos_chroot/var/lib/rpm

Create the RPM database