Sudo file configuration examples for Db2 environments

Configuring sudo access on AIX for Db2 source and target environments

Sudo access to ps on the AIX operating system is required for the detection of listeners with non-standard configurations on both source and target environments. Super-user access level is needed to determine the TNS_ADMIN environment variable of the user running the listener (typically db2, the installation owner). From TNS_ADMIN, the Delphix OS user delphix_os can derive connection parameters. 

Example: AIX /etc/sudoers entries for a Delphix Source

Defaults:delphix_os !requiretty
delphix_os ALL=NOPASSWD:/bin/ps

In addition to sudo access to the mount, umount, and ps commands on AIX target hosts, Delphix also requires sudo access to nfso. This is required on target hosts for the Delphix Engine to monitor the NFS read-write sizes configured on the AIX system. Super-user access level is needed to run the nfso command.

Example: AIX /etc/sudoers File for a Delphix Target

Defaults:delphix_os !requiretty
delphix_os ALL=NOPASSWD: \
/usr/sbin/mount, \
/usr/sbin/umount, \
/usr/sbin/nfso, \
/usr/bin/ps

Configuring sudo access on Linux for Db2 source and target environments

On a Linux target, sudo access to mount, umount, mkdir, and rmdir is required. 
Example: Linux /etc/sudoers file for a Delphix target for DB2

Examples of limiting sudo access for the Delphix OS user

In situations where security requirements prohibit giving the Delphix user root privileges to mount, unmount, make directory, and remove directory on the global level, it is possible to configure the sudoers file to provide these privileges only on specific mount points or from specific Delphix Engines, as shown in these two examples.

The Delphix Engines tests its ability to run the mount command using sudo on the target environment by issuing the sudo mount command with no arguments. Many of the examples shown in this topic do not allow that. This causes a warning during environment discovery and monitoring, but otherwise does not cause a problem. If your VDB operations succeed, it is safe to Ignore this warning.

However, some users configure the security on the target environments to monitor sudo failures and lock out the offending account after some threshold. In those situations, the failure of the sudo commands might cause the delphix_os account to become locked. One work-around for this situation is to increase the threshold for locking out the user account. Another option is to modify /etc/sudoers to permit the delphix_os user to run mkdir, rmdir, umount and mount command without parameters.

Note that the following examples are for illustrative purposes and the sudo file configuration options are subject to change.

Example 1

This example restricts the delphix_os user's use of sudo privileges to the directory /db2.

Note that wildcards are allowed for the options on mount and umount because those commands expect a fixed number of arguments after the options. The option wildcard on the mount command also makes it possible to specify the file-system being mounted from the Delphix Engine.

However, wildcards are not acceptable on mkdir and rmdir because they can have any number of arguments after the options. For those commands, you must specify the exact options (-p, -p -m 755) used by the Delphix Engine.

Example /etc/sudoers File Configuration on the Target Environment for sudo Privileges on the VDB Mount Directory Only (Linux OS)

Defaults:delphix_os !requiretty
delphix_os ALL=(root) NOPASSWD: \
/bin/mount  *        /db2/*, \
/bin/umount *        /db2/*, \
/bin/umount          /db2/*, \
/bin/mkdir -p        /db2/*, \
/bin/mkdir -p -m 755 /db2/*, \
/bin/mkdir           /db2/*, \
/bin/rmdir           /db2/*

Example 2

This example restricts the delphix_os user's use of sudo privileges to the directory /db2, restricts the mount commands to a specific Delphix Engine hostname and IP, and does not allow user-specified options for the umount command.

This configuration is more secure, but there is a tradeoff with deployment simplicity. This approach would require a different sudo configuration for targets configured for different Delphix Engines.

A Second Example of Configuring the /etc/sudoers File on the Target Environment for Privileges on the VDB Mount Directory Only, and Allows Mounting Only from a Single Server (Linux OS)

Defaults:delphix_os !requiretty
delphix_os ALL=(root) NOPASSWD: \
/bin/mount           <delphix-server-name>* /db2/*, \
/bin/mount *         <delphix-server-name>* /db2/*, \
/bin/mount           <delphix-server-ip>*   /db2/*, \
/bin/mount *         <delphix-server-ip>*   /db2/*, \
/bin/mount "", \
/bin/umount          /db2/*, \
/bin/umount *        /db2/*, \
/bin/mkdir [*]       /db2/*, \
/bin/mkdir           /db2/*, \
/bin/mkdir -p        /db2/*, \
/bin/mkdir -p -m 755 /db2/*, \
/bin/rmdir           /db2/*