h1. Linux Agent Configuration
{anchor:agent_config_htm}
The Linux Agent installer automatically sets default parameters for the configuration file located in:
{code}
/etc/buagent/agent_config
{code}
After making changes to this file you need to restart the Agent daemon. To restart the Agent use:
{code}
# /etc/init.d/buagent restart
{code}
h3. Agent Configuration Options
|| Option Name || Default Value || Description ||
| *ConfDir* | {color:#0000ff}/etc/buagent{color} | Configuration directory path. |
| *CacheDir* | {color:#0000ff}/var/cache/buagent{color} | Directory to store cache files. The Linux Agent uses files to store changed blocks during the copy-on-write snapshot process. The Agent will also write a large file containing MD5 checksums for all of the blocks when the agent needs to re-sync CDP change tracking after a reboot. By default this is {color:#0000ff}/var{color}. If your {color:blue}/var{color} partition does not have much free space or is small, you may need to change this to a directory that has more free space. It is recommended that you have at least 1 or 2 GB of free space for this directory. The temporary files created here will be automatically cleaned up after backup operations. |
| *DbDir* | {color:#0000ff}/var/db/buagent{color} | Directory to store db files. The CDP for Data Centers edition automatically configured Agent RSA Keys for CDP Servers (only the Control Server RSA key is manually added to the Agent). The CDP Server RSA Keys that are configured on the Agent by the Control Server are stored here. |
| *DiskAsPartition* ({color:#fd4703}{*}New in Version 2.20 / Linux Agent 1.70.1{*}{color}) | {color:#0000ff}No{color}\\ | Set to "Yes" to enable Linux Agent to recognize Disks with No Partition Table. For more information, see [kb:Linux Agent - Recognize Disks without a Partition Table - CDP 2.20.1]. \\ |
| *LibDir* | {color:#0000ff}/usr/lib/buagent{color} | This directory contains executables called by the Agent such as LVM Backup and Restore utilities. \\
Control Panel user authentication Perl scripts are stored here and include:
* buagentauth (default Linux authentication)
* buagentauth.cpanel (CPanel)
* buagentauth.directadmin (Direct Admin)
* buagentauth.ensim (Ensim)
* buagentauth.plesk (Plesk) |
| *MaxCacheBlocks* | configured at install time to 1/4 physical memory | The Linux Agent CDP device driver temporarily stores changed blocks in memory during the copy-on-write snapshot process. This parameter specifies a hard limit on the number of 4KB Kernel memory pages that can be used to store changed blocks. This may need to be set higher if the Agent Backup process fails with messages in {color:blue}/var/log/messages{color} from the kernel about max configured cache memory reached. |
| *ModulesDir* | {color:#0000ff}/lib/modules/buagent{color} | Directory where CDP device driver kernel modules are located. |
| *UserAuthEnabled* | configured at install time | Set to "Yes" to enable control panel authentication. See [Enabling Control Panel Module|Linux Agent CLI - Managing Control Panel Add-On#cpanel_htm]. |
| *UserAuthProg* | | If User authentication is enabled, this is the external program that is used for authentication. Leaving this commented out allows buagent to guess the proper buagent auth script from LibDir. See [Enabling Control Panel Module|Linux Agent CLI - Managing Control Panel Add-On#cpanel_htm]. |
| *ChildUID* | configured at install time when user buagent is added | Numeric UID for network privilege separation. The buagent has a separate process used for network communication that *does not* have root privileges for added security. |
| *ChildGID* | configured at install time when group buagent is added | Numeric UID for network privilege separation. The buagent has a separate process used for network communication that *does not* have root privileges for added security. |
| *MaxClients* | 20 | Maximum network connection from CDP Servers allowed. |
| *ListenAddress* | 0.0.0.0 all IPs | CDP Agent will listen for requests on this IP. Default is 0.0.0.0, meaning the Agent accepts connections on any IP address configured on your Linux Server. |
| *Port* | 1167 | TCP port the CDP Agent will listen on. |
| *PidFile* | {color:#0000ff}/var/run/buagent.pid{color} | File to which CDP Agent will write its process identifier for {color:#0000ff}/etc/init.d/buagent{color} to shut it down. |
| *LockFile* | {color:#0000ff}/var/lock/buagent.lock{color} | CDP Agent lock file. Prevents multiple Agents from starting at the same time. |
| *IPAuthentication* ({color:#fd4703}{*}New in Version 1.56{*}{color}) | no | If set to "Yes," the Agent looks for a file in the {color:blue}server.allow{color} directory matching the IP address of an incoming connection before performing RSA Key authentication. The new default as of Linux Agent 1.56 is "No." This means the Agent will only perform RSA Key authentication and will not check the source IP address of the connecting CDP Server. \\
*Recommended Setting:* RSA Key authentication is VERY strong and is just like using SSH with RSA or DSA key authentication (authentication without a password). For added security, you can have the Agent check that the source IP address of the connecting CDP Server attempting to authenticate is a configured IP address in the /etc/buagent/server.allow directory which contains CDP Server RSA public keys named with the source IP address of the CDP Server. |
| *Timeout* ({color:#fd4703}{*}New in Version 1.56{*}{color}) | 160 | Agent timeout in seconds. Default value is 160 seconds. It is recommended you raise this default to at least 600 seconds if you are connecting over a Wide Area Network. |
Run the following command to list all configuration options:
{code}
#cat /etc/buagent/agent_config
{code}
or
{code}
#less /etc/buagent/agent_config
{code}
!config1.png!\\ {excerpt:hidden=true}Instructions on how to change Linux Agent configuration.{excerpt}
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{anchor:agent_config_htm}
The Linux Agent installer automatically sets default parameters for the configuration file located in:
{code}
/etc/buagent/agent_config
{code}
After making changes to this file you need to restart the Agent daemon. To restart the Agent use:
{code}
# /etc/init.d/buagent restart
{code}
h3. Agent Configuration Options
|| Option Name || Default Value || Description ||
| *ConfDir* | {color:#0000ff}/etc/buagent{color} | Configuration directory path. |
| *CacheDir* | {color:#0000ff}/var/cache/buagent{color} | Directory to store cache files. The Linux Agent uses files to store changed blocks during the copy-on-write snapshot process. The Agent will also write a large file containing MD5 checksums for all of the blocks when the agent needs to re-sync CDP change tracking after a reboot. By default this is {color:#0000ff}/var{color}. If your {color:blue}/var{color} partition does not have much free space or is small, you may need to change this to a directory that has more free space. It is recommended that you have at least 1 or 2 GB of free space for this directory. The temporary files created here will be automatically cleaned up after backup operations. |
| *DbDir* | {color:#0000ff}/var/db/buagent{color} | Directory to store db files. The CDP for Data Centers edition automatically configured Agent RSA Keys for CDP Servers (only the Control Server RSA key is manually added to the Agent). The CDP Server RSA Keys that are configured on the Agent by the Control Server are stored here. |
| *DiskAsPartition* ({color:#fd4703}{*}New in Version 2.20 / Linux Agent 1.70.1{*}{color}) | {color:#0000ff}No{color}\\ | Set to "Yes" to enable Linux Agent to recognize Disks with No Partition Table. For more information, see [kb:Linux Agent - Recognize Disks without a Partition Table - CDP 2.20.1]. \\ |
| *LibDir* | {color:#0000ff}/usr/lib/buagent{color} | This directory contains executables called by the Agent such as LVM Backup and Restore utilities. \\
Control Panel user authentication Perl scripts are stored here and include:
* buagentauth (default Linux authentication)
* buagentauth.cpanel (CPanel)
* buagentauth.directadmin (Direct Admin)
* buagentauth.ensim (Ensim)
* buagentauth.plesk (Plesk) |
| *MaxCacheBlocks* | configured at install time to 1/4 physical memory | The Linux Agent CDP device driver temporarily stores changed blocks in memory during the copy-on-write snapshot process. This parameter specifies a hard limit on the number of 4KB Kernel memory pages that can be used to store changed blocks. This may need to be set higher if the Agent Backup process fails with messages in {color:blue}/var/log/messages{color} from the kernel about max configured cache memory reached. |
| *ModulesDir* | {color:#0000ff}/lib/modules/buagent{color} | Directory where CDP device driver kernel modules are located. |
| *UserAuthEnabled* | configured at install time | Set to "Yes" to enable control panel authentication. See [Enabling Control Panel Module|Linux Agent CLI - Managing Control Panel Add-On#cpanel_htm]. |
| *UserAuthProg* | | If User authentication is enabled, this is the external program that is used for authentication. Leaving this commented out allows buagent to guess the proper buagent auth script from LibDir. See [Enabling Control Panel Module|Linux Agent CLI - Managing Control Panel Add-On#cpanel_htm]. |
| *ChildUID* | configured at install time when user buagent is added | Numeric UID for network privilege separation. The buagent has a separate process used for network communication that *does not* have root privileges for added security. |
| *ChildGID* | configured at install time when group buagent is added | Numeric UID for network privilege separation. The buagent has a separate process used for network communication that *does not* have root privileges for added security. |
| *MaxClients* | 20 | Maximum network connection from CDP Servers allowed. |
| *ListenAddress* | 0.0.0.0 all IPs | CDP Agent will listen for requests on this IP. Default is 0.0.0.0, meaning the Agent accepts connections on any IP address configured on your Linux Server. |
| *Port* | 1167 | TCP port the CDP Agent will listen on. |
| *PidFile* | {color:#0000ff}/var/run/buagent.pid{color} | File to which CDP Agent will write its process identifier for {color:#0000ff}/etc/init.d/buagent{color} to shut it down. |
| *LockFile* | {color:#0000ff}/var/lock/buagent.lock{color} | CDP Agent lock file. Prevents multiple Agents from starting at the same time. |
| *IPAuthentication* ({color:#fd4703}{*}New in Version 1.56{*}{color}) | no | If set to "Yes," the Agent looks for a file in the {color:blue}server.allow{color} directory matching the IP address of an incoming connection before performing RSA Key authentication. The new default as of Linux Agent 1.56 is "No." This means the Agent will only perform RSA Key authentication and will not check the source IP address of the connecting CDP Server. \\
*Recommended Setting:* RSA Key authentication is VERY strong and is just like using SSH with RSA or DSA key authentication (authentication without a password). For added security, you can have the Agent check that the source IP address of the connecting CDP Server attempting to authenticate is a configured IP address in the /etc/buagent/server.allow directory which contains CDP Server RSA public keys named with the source IP address of the CDP Server. |
| *Timeout* ({color:#fd4703}{*}New in Version 1.56{*}{color}) | 160 | Agent timeout in seconds. Default value is 160 seconds. It is recommended you raise this default to at least 600 seconds if you are connecting over a Wide Area Network. |
Run the following command to list all configuration options:
{code}
#cat /etc/buagent/agent_config
{code}
or
{code}
#less /etc/buagent/agent_config
{code}
!config1.png!\\ {excerpt:hidden=true}Instructions on how to change Linux Agent configuration.{excerpt}
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