7.2. Synchronization Tools
Turbolinux Cluster LoadBalancer 10 comes with two different synchronization tools: one to synchronize the configuration, and one to synchronize content. These programs are named tlclb_config_sync and tlclb_content_sync. They will help you to maintain consistency among the servers in the cluster.
The synchronization tools require that an SSH daemon be running on all the servers that are to receive the updated content or configuration. They will work with any system on which you have installed Turbolinux Cluster LoadBalancer 10, as SSH is included. For tlclb_config_sync, this is not a problem, because you will only need the configuration file on systems running the Cluster Server daemon. For content, you will have to synchronize those systems without SSH by hand.
7.2.1. tlclb_content_sync
The tlclb_content_sync utility is used to ensure that all of your cluster nodes contain the same content. The program can be started from the command prompt, or it can be started from the turboclusteradmin program. To synchronize your content, simply follow these steps:
Start the utility from the command line:
# tlclb_content_sync
You can also start it from the turboclusteradmin program by selecting the `Content Synchronization Tool' menu item. Both will take you to the same place.
A screen will appear with a list of directories and a list of servers. You can use the TAB key to move between the two lists. There may be more entries than appear on the screen -- you can use the up and down cursor keys to scroll through the lists.
The list of directories details the content that you want to synchronize. Everything within each directory listed will be copied, including all subdirectories. Initially, in the "Directories to synchronize" field, you will see Apache's document root structure listed. On Turbolinux 10 Server, this directory structure is /var/www/html.
To add or remove a directory from the list, click on the `Edit Dir' button at the bottom of the screen. This will bring up a new screen, allowing you to add, remove, or edit the directory entries. Click `Done' when you have selected the appropriate directories that you want to be synchronized.
To change which servers will receive the synchronized content, click on the `Edit Servers' button. This will bring up the list of systems along with buttons to add, remove, and edit the server names. Hit `Done' when you have the proper list of servers that you want to synchronize.
Initially all servers that were added as cluster nodes in the configuration program will be listed. If any of these nodes are not running the SSH daemon, you will need to remove them from the list or install SSH.
If you leave a server listed that does not have the SSH daemon installed and running, you will get a warning message when you start the synchronization process. The warning message will tell you that the connection was refused by the server, and that synchronization could not be completed due to errors.
Once you have the correct directories and servers shown, hit the `Start' button.
If this is the first time that you have synchronized with a particular server, you will be prompted for the root password on that system. The underlying SSH tools require this step the first time, but will remember the password for reuse later.
Input the root password and click on the `OK' button.
The program will go through the list of servers, contacting each one, sending the contents of all the directories.
If any errors occur, you will be prompted with a message telling you what went wrong. Most likely any error will be caused by a system that is down or one that is not running the SSH daemon that comes with Cluster Server. You can remove the server so that it will not give any warning messages in the future.
When the synchronization process has completed, you will be told whether the operation was a success or if there was some difficulty connecting to some of the servers. Click on the `Close' button to exit the utility. If there were any errors, you will want to resolve them and try again.
7.2.2. tlclb_config_sync
The tlclb_config_sync utility is used to synchronize the Turbolinux Cluster LoadBalancer 10 configuration files. Like the tlclb_config_sync program, it can be run from the command line or started from turboclusteradmin. To synchronize your configuration, simply follow these steps:
Start the utility from the command line:
# tlclb_config_sync
You can also start it from the turboclusteradmin program by selecting the `Configuration Synchronization Tool' menu item. Both will take you to the same place.
A list of servers will appear. Initially all servers that were added as nodes or ATMs in the configuration program will be listed.
You will need to remove any servers listed that do not have Turbolinux Cluster LoadBalancer 10 installed. To do this, highlight the particular server and hit the `Remove' button. The system will be immediately removed from the list.
If you leave a server listed that does not have Turbolinux Cluster LoadBalancer 10 installed, you will get a warning message when you start the synchronization process. The warning message will tell you that the connection was refused by the server, and that synchronization could not be completed due to errors.
Add any servers that are missing from the list. To do this, click on the `Add' button and type the name of the server in the box provided. Click `OK' and the server will be added to the list.
Once you have the correct list of servers shown, click on the `Start' button. If this is the first time that you have synchronized with a particular server, you will be prompted for the root password on that system.
The program will go through the list of servers, contacting each one, sending the updated configuration file.
If any errors occur, you will be prompted with a message telling you what went wrong. Most likely any error will be caused by a system that is down or one that is not running the SSH daemon that comes with Cluster Server. You can remove the server from the list so that it will not give any warning messages in the future.
When the synchronization process has completed, you will be told whether the operation was a success or if there was some difficulty connecting to some of the servers. Click on `Close' to exit the utility. If there were any errors, you will want to resolve them and try again.