HP Dynamic Root Disk (DRD) 4.2Commands that Communicate with Other Processes

•if [[ $SW_SESSION_IS_UPDATE -ne 1 && $SW_SESSION_IS_DRD -ne 1 ]] then

vxdctl stop >/dev/null 2>&1 fi

•kill_named_procs wlmcomd SIGTERM > /dev/null 2>&1

4.2Commands that Communicate with Other Processes

Look for commands that communicate with other process—for example, communications through sockets, RPC calls, or named pipes.

Unsafe Examples:

•vxdg bootdg

The vxdg command attempts to contact the vxconfigd daemon, which was started on the booted system.

Suggested Resolutions:

Follow the steps below to make the logic DRD-safe:

1.First, determine if the communication is DRD-safe (or not):

a.If the communication occurs with a process started within the runcmd environment, the communication is DRD-safe and no action is needed. A process has been started within the runcmd environment if the environment variable SW_SESSION_IS_DRD is set to 1 inside that process.

b.If the communication occurs with a process on a different system (that is, remote communication), the communication is DRD-safe and no action is needed. Remote communication is considered safe because the information obtained from a remote system is unlikely to differ based on whether it was obtained on behalf of the booted system image or the inactive system image.

c.If the communication occurs with a process started outside of the runcmd environment, the communication may not be DRD-safe. Whether or not the communication is DRD-safe depends on the results of the communication. For example, if the communication is just to establish if a process is currently running, the result is DRD-safe. If the communication is to retrieve information from the running process and that information is not relevant to the inactive system image, the result is not DRD-safe. The owner of the logic must examine the information returned and how it is used to determine if the result will adversely affect the inactive system image. While making this examination, it is important to remember that the inactive system image could have an entirely different software configuration than the booted system image. If the logic is not safe, it may be necessary to detect that this is a runcmd environment (that is, SW_SESSION_IS_DRD=1), and modify the logic to retrieve the information from the inactive system image instead of the running system image.

2.If the logic is unsafe, use the SW_SESSION_IS_DRD environment variable to determine that the command is executing in a runcmd environment and either skip the unsafe logic or re- write the logic in a safe manner. For example, a command may have a “DRD mode” that can be activated by a command-line option. In this case, the unsafe logic could be modified to detect the runcmd environment and add the “DRD mode” option to the command line, thus making the execution of the command DRD-safe.