Using Daemon Mode (Technical Preview)

Technical Preview Daemon mode is available in the @next version of Zowe CLI. The Zowe CLI @next release is a technical preview. Technical previews are for only testing and are not ready for production. Your feedback is valued and appreciated.

If you already installed the supported version @zowe-v1-lts, switch versions to try this feature. Daemon mode will be included in the next major Zowe release, V2.0.0-LTS. You can also install the @next release of Zowe CLI.

Feature overview

Daemon mode significantly improves the performance of Zowe CLI commands by running Zowe CLI as a persistent background process (daemon). Running Zowe CLI as daemon lets Zowe absorb the one-time startup of Node.js modules, which results in significantly faster responses to Zowe commands.

Preparing for installation

Review the following installation notes before you configure Zowe CLI to run in daemon mode:

• Daemon mode does not function on z/OS UNIX System Services (USS) systems.
• When you want to run Zowe CLI to run in daemon mode on z/Linux operating systems, you must build the daemon mode binary on the z/Linux systems. For information about how to build the binary, see Configure daemon mode on z/Linux operating systems. The sections Enable daemon mode and Disable daemon mode (in this article) do not apply to running Zowe CLI in daemon mode on z/Linux operating systems.
• We do not recommend using daemon mode in an environment where multiple users use the same system. For example, a shared Linux server.
• To enable daemon mode, ensure that you installed the @next release of Zowe CLI.
• When you are running Zowe on a Windows operating system in a virtual environment (for example, Windows Sandbox), you might receive an error message that indicates that a library named VCRUNTIME140.dll is missing. To correct the error, install Visual C++ Redistributable for Visual Studio 2015. For more information, see Download Visual C++ Redistributable for Visual Studio 2015.

Enable daemon mode

The following steps describe how to enable daemon mode and how to configure Zowe to run constantly in daemon mode.

1. Open a terminal window and issue the following command:

   zowe daemon enable

   The command copies the Zowe executables for your operating system into the $ZOWE_CLI_HOME/bin (.zowe/bin) directory. The next command that you issue starts the daemon.

2. Add the path to the Zowe executable to your PATH environment variable. For example:

   C:\Users\<user_ID>\.zowe\bin

   Important! Ensure that you position the path to your Zowe executables before the path into which NPM installed the Node.js script. For example, C:\Program Files\nodejs\zowe.cmd. For information about configuring environment variables, see the documentation for your computer's operating system.

   Alternative configuration: By default, the daemon binary creates or reuses a file in the user's home directory each time a Zowe CLI command runs. In some cases, this behavior might be undesirable. For example, the home directory resides on a network drive and has poor file performance. To change the location that the daemon uses, set the following environment variable for your operating system:

   • Windows: ZOWE_DAEMON_LOCK

     Specify an alternative path to the lock file that restricts access to the named pipe that the daemon uses for communication.

     Default: %HOMEPATH%\.zowe-daemon.lock

   • Linux and macOS: ZOWE_DAEMON

     Specify an alternative path to the socket that the daemon uses for communication.

     Default: $HOME/.zowe-daemon.sock

   Note: Complete the environment variable configuration step (Step 2) only once.

The following example illustrates running Zowe commands with the daemon mode enabled:

zowe --version
Starting a background process to increase performance ...
7.0.0-next.202110211759

zowe --version
7.0.0-next.202110211759

Disable daemon mode

You can disable Zowe from running in daemon mode at any time. For example, daemon mode lacks functionality that you desire, such as viewing colored-coded commands.

Open a terminal window and issue the following command:

zowe daemon disable

The disable command removes the Zowe executables from your .zowe/bin directory and disables daemon mode.

Running Zowe commands in daemon mode

When you run Zowe in daemon mode, you run all Zowe commands as you normally run them. The first time you run a command, it starts the daemon in the background automatically and runs your desired Zowe command. Since the first Zowe command starts the daemon, the first command usually runs slower than a traditional Zowe command. However, subsequent Zowe commands run significantly faster. The daemon continues to run in the background until you close your terminal window.

Note: When you are running Zowe CLI in daemon using a Git Bash terminal on a Windows operating system, special characters might display using the wrong code page. For example, the default code page 437 renders a form-feed character (\f) as an emoji (♀️). To correct the problem, issue the command chcp.com 65001 to change the code page to UTF-8. If you want the change to be persistent, add the command to your .bashrc file.