Tag: lsyncd

People looking to create a load balanced web server solution often ask, how can they keep their web servers in sync with each other? There are many ways to go about this: NFS, lsync, rsync, etc. This guide will discuss using Lsyncd to keep their slave web servers in sync every 20 seconds.

Taken directly from the vendors website, Lsyncd watches a local directory trees event monitor interface (inotify or fsevents). It aggregates and combines events for a few seconds and then spawns one (or more) process(es) to synchronize the changes. By default this is rsync. Lsyncd is thus a light-weight live mirror solution that is comparatively easy to install not requiring new filesystems or blockdevices and does not hamper local filesystem performance.

This article will be broken down by the following operating systems, as each has some minor catches. Simply scroll down to your desired operating system listed below:
CentOS 6 – How To Install And Configure Lsyncd
CentOS 7 – How To Install And Configure Lsyncd
Ubuntu 12.04 – How To Install And Configure Lsyncd
Ubuntu 14.04 – How To Install And Configure Lsyncd

CentOS 6 – How To Install And Configure Lsyncd
Install Lsyncd via yum. Please note, this will automatically setup:
– Lsyncd 2.1.5
– /etc/logrotate.d/lsyncd
– /etc/init.d/lsyncd
– Provide a place holder for /etc/lsyncd.conf

Install it by running:

yum -y install lsyncd
chkconfig lsyncd on

Now setup the lsyncd configuration by:

vim /etc/lsyncd.conf
 
settings {
   logfile = "/var/log/lsyncd/lsyncd.log",
   statusFile = "/var/log/lsyncd/lsyncd-status.log",
   statusInterval = 20
}
servers = {
 "x.x.x.x",
 "x.x.x.x",
 "x.x.x.x"
}
 
for _, server in ipairs(servers) do
sync {
    default.rsyncssh,
    source="/var/www/",
    host=server,
    targetdir="/var/www/",
    excludeFrom="/etc/lsyncd-excludes.txt",
    rsync = {
        compress = true,
        archive = true,
        verbose = true,
        rsh = "/usr/bin/ssh -p 22 -o StrictHostKeyChecking=no"
    }
}
end

Create the place holder for lsyncd-excludes.txt

touch /etc/lsyncd-excludes.txt

Finally, start the service

chkconfig lsyncd on
service lsyncd start

CentOS 7 – How To Install And Configure Lsyncd

Install Lsyncd via yum. Please note, this will automatically setup
– Lsyncd 2.1.5
– /etc/logrotate.d/lsyncd
– /etc/init.d/lsyncd
– Provide a place holder for /etc/lsyncd.conf

Install it by running

yum -y install lsyncd
systemctl enable lsyncd.service

Now setup the lsyncd configuration by:

vim /etc/lsyncd.conf
 
settings {
   logfile = "/var/log/lsyncd/lsyncd.log",
   statusFile = "/var/log/lsyncd/lsyncd-status.log",
   statusInterval = 20
}
servers = {
 "x.x.x.x",
 "x.x.x.x",
 "x.x.x.x"
}
 
for _, server in ipairs(servers) do
sync {
    default.rsyncssh,
    source="/var/www/",
    host=server,
    targetdir="/var/www/",
    excludeFrom="/etc/lsyncd-excludes.txt",
    rsync = {
        compress = true,
        archive = true,
        verbose = true,
        rsh = "/usr/bin/ssh -p 22 -o StrictHostKeyChecking=no"
    }
}
end

Create the place holder for lsyncd-excludes.txt and /var/log/lsyncd:

touch /etc/lsyncd-excludes.txt
mkdir /var/log/lsyncd

Finally, start the service

systemctl start lsyncd.service

Ubuntu 12.04 – How To Install Lsyncd

Install Lsyncd via apt. Please note, this will automatically setup
– Lsyncd 2.0.4
– /etc/init.d/lsyncd

But it will not setup:
– /etc/logrotate.d/lsyncd
– /etc/lsyncd/lsyncd.conf.lua

Install it by running:

apt-get update
apt-get install lsyncd

Now setup the lsyncd configuration by:

mkdir /etc/lsyncd
vim /etc/lsyncd/lsyncd.conf.lua
 
settings = {
logfile = "/var/log/lsyncd/lsyncd.log",
statusFile = "/var/log/lsyncd/lsyncd-status.log",
statusInterval = 20
}

servers = {
 "x.x.x.x",
 "x.x.x.x",
 "x.x.x.x"
}

for _, server in ipairs(servers) do
sync { 
    default.rsync, 
    source="/var/www/",
    target=server..":/var/www/",
    excludeFrom="/etc/lsyncd/lsyncd-excludes.txt",
    rsyncOps={"-e", "/usr/bin/ssh -o StrictHostKeyChecking=no", "-avz"}
}
end

Create the place holder for lsyncd-excludes.txt and logs directory

touch /etc/lsyncd/lsyncd-excludes.txt
mkdir /var/log/lsyncd

Setup log rotate script

vim /etc/logrotate.d/lsyncd

/var/log/lsyncd/*log {
    missingok
    notifempty
    sharedscripts
    postrotate
    if [ -f /var/lock/lsyncd ]; then
      /usr/sbin/service lsyncd restart > /dev/null 2>/dev/null || true
    fi
    endscript
}

Finally, start the service

service lsyncd start

Ubuntu 14.04 and 16.04 – How To Install Lsyncd

Install Lsyncd via apt. Please note, this will automatically setup
– Lsyncd 2.1.5
– /etc/init.d/lsyncd

But it will not setup:
– /etc/logrotate.d/lsyncd
– /etc/lsyncd/lsyncd.conf.lua

Install it by running

apt-get update
apt-get install lsyncd

Now setup the lsyncd configuration by:

mkdir /etc/lsyncd
vim /etc/lsyncd/lsyncd.conf.lua
 
settings {
   logfile = "/var/log/lsyncd/lsyncd.log",
   statusFile = "/var/log/lsyncd/lsyncd-status.log",
   statusInterval = 20
}
servers = {
 "x.x.x.x",
 "x.x.x.x",
 "x.x.x.x"
}
 
for _, server in ipairs(servers) do
sync {
    default.rsyncssh,
    source="/var/www/",
    host=server,
    targetdir="/var/www/",
    excludeFrom="/etc/lsyncd/lsyncd-excludes.txt",
    rsync = {
        compress = true,
        archive = true,
        verbose = true,
        rsh = "/usr/bin/ssh -p 22 -o StrictHostKeyChecking=no"
    }
}
end

Create the place holder for lsyncd-excludes.txt and logs directory

touch /etc/lsyncd/lsyncd-excludes.txt
mkdir /var/log/lsyncd

Setup log rotate script

vim /etc/logrotate.d/lsyncd

/var/log/lsyncd/*log {
    missingok
    notifempty
    sharedscripts
    postrotate
    if [ -f /var/lock/lsyncd ]; then
      /usr/sbin/service lsyncd restart > /dev/null 2>/dev/null || true
    fi
    endscript
}

Finally, start the service

service lsyncd start

Note: On Ubuntu 16.04, if ‘service lsyncd start’ does not start daemon, then manually start lsyncd, which will allow systemd to work with it from here on out by running:

/usr/bin/lsyncd /etc/lsyncd/lsyncd.conf.lua
service lsyncd stop
service lsyncd start