synctool

Synctool is a comprehensive administrative tool that is ideal for managing clusters of computers. It simplifies the task of copying configuration files to groups of machines in your cluster. Synctool ensures that the configuration on a group of machines is synchronized effortlessly. Additionally, if needed, Synctool can restart or reload any daemons without any difficulty.

Synctool is easily extendable, which allows it to perform a wide range of other administrative tasks. These include checking daemons, checking free disk space, installing packages, and any other task that you want it to do. The software was developed by Walter de Jong between 2003 and 2006.

Synctool simplifies system administration by working with the following concepts:

• A host can be part of one or more groups or classes.

• Files are designated a class by means of filename extension.

• The 'overlay' directory tree contains the files and directories that should be copied to the target host.

• When certain files are updated, a script (eg, /etc/init.d/daemon restart) should be executed.

• Simplicity. Synctool leverages the power of rsync and ssh to distribute the files.

• Extendibility. The software can be made more powerful by writing plugin scripts.

Installation of Synctool is straightforward:

• Copy the contents of the bin/ directory to your local software directory, for example, /usr/local/bin/. These executables should be available on every node in your cluster. It is easy to use a shared filesystem for this or use other file distribution mechanisms.

• Set up a Synctool repository on the master node:

mkdir /var/lib/synctool

• Usually, the masterdir is only accessible by root:

chown root.root /var/lib/synctool
chmod 700 /var/lib/synctool

• Set up the initial Synctool repository directories:

mkdir /var/lib/synctool/overlay
mkdir /var/lib/synctool/delete
mkdir /var/lib/synctool/tasks
mkdir /var/lib/synctool/scripts

• Edit the configuration file:

cp synctool.conf.example /var/lib/synctool/synctool.conf
vi /var/lib/synctool/synctool.conf

• Edit the .sh scripts to contain the correct path names:

vi /usr/local/bin/synctool-local.sh
vi /usr/local/bin/synctool.sh

It is worth noting that you should decide whether or not to administer your master node with Synctool as well. The hosts that are under Synctool's control are listed in synctool.conf. Therefore, if you want to exclude it, leave it out of the config file.

Synctool also features a wrapper script synctool.sh that deploys with it by default. This script does the following:

• Rsync the repository to all nodes

• Run Synctool on all nodes via ssh.

Synctool leverages rsync with ssh to copy files to all nodes. Therefore, you will need to set up ssh with passwordless login for root from the masternode to the cluster nodes. However, this has certain security implications, so ensure you understand every security aspect before opening up the nodes.

Overall, Synctool is an exceptional tool, ideal for system administrators looking to simplify cluster management.