Master Command-Line Deployments with PSSH & PSCP: A Step-by-Step Guide

HULK already provides S3, Git, and SVN deployment systems; this article focuses on direct command‑line deployment of projects, covering both single‑file and full‑project releases.

1. Understand PSSH and PSCP

PSSH runs commands in parallel on target servers. Basic syntax: pssh -h "hosts.txt" -i "cmd" Key options:

-h: specify a file containing host list

-H: specify hosts as a space‑separated string

-p: set parallelism count

-i: show command output

-x "-o StrictHostKeyChecking=no": skip first‑login confirmation

Success example:

[1] 14:54:03 [SUCCESS] hulk001 [2] 14:54:03 [SUCCESS] hulk002

Failure example:

[1] 15:07:35 [FAILURE] hulk001 Exited with error code 1

Common error codes include 1, 127, 255.

2. Establish Trust Between Servers

Generate an SSH key pair with ssh-keygen (accept defaults). The generated id_rsa (private) and id_rsa.pub (public) are stored in ~/.ssh. Copy the public key to the target machine’s authorized_keys file for the deployment user, then test password‑less login.

3. Deploy Code

Run the deployment script:

~/project/pub(test) >> sh tools/deploy.sh src/application/controller/IndexController.php

The script prompts for the branch (dev, master, test) and the target environment (test, beta, prod). After confirming the host list and file list, it packages the files, compares MD5 checksums, uploads to a baseline machine, backs up originals, and extracts the new version.

Example prompts and selections:

=== Choose branch === 1 dev 2 master 3 test

Enter branch [master]: test

=== Switch to [test] branch ===

=== Pull remote branch if needed ===

After confirming, the script uploads files in parallel using PSCP, then deploys them with PSSH. Successful upload and deployment messages are shown for each host.

Rollback can be performed with:

sh tools/deploy-revert.sh ~/deploy_bak/project_name/20170601093937.tgz hulk001

4. Perfect Whole‑Project Deployment

For large projects, the same process scales: package, upload, and deploy across all servers, then verify. The article notes that operations like ls -sf are not atomic; instead, use ln && mv (which internally performs a rename) to ensure safe updates.

Rollback for all machines is executed with:

sh tools/deploy-revert.sh ~/deploy_bak/project_name/20170601095657.tgz

Overall, the guide emphasizes a simple, fast, and reliable command‑line deployment workflow.