Version control is essential for any DevOps engineer. You’ll be writing infrastructure code, automation scripts, and configuration files that need to be tracked, shared, and versioned just like application code.
Core Git Workflow
Understanding the basic Git workflow is crucial:
Working Directory → git add → Staging Area → git commit → Local Repository → git push → Remote Repository
Why the Staging Area?
The staging area acts as a buffer between your working directory and commits. This allows you to:
- Review changes before committing
- Stage only specific files or parts of files
- Create focused, logical commits
Essential Commands
# Check status of working directory and staging area
git status
# View commit history
git log
git log --oneline --graph # Compact view with branch visualization
# Configure Git (do this once)
git config --list
git config --global user.name "Your Name"
git config --global user.email "your.email@example.com"
Repository Setup
Connecting Local to Remote
# Add remote repository
git remote add origin git@gitlab.com:username/repository.git
# Push and set upstream tracking
git push --set-upstream origin master
Branching Strategies
Feature vs Trunk-Based Development
Feature-Based (Traditional):
- Create separate branches for each feature/bugfix
- Merge back to main branch via pull requests
- Good for larger teams, complex features
Trunk-Based (Modern DevOps):
- Work directly on main branch or very short-lived branches
- Frequent small commits
- Enables faster CI/CD cycles
- Requires good testing practices
Branch Operations
# Switch to existing branch
git checkout branch_name
# Create and switch to new branch
git checkout -b branch_name
# Push new branch to remote
git push --set-upstream origin branch_name
# Delete local branch after merge
git branch -d branch_name
Handling Changes and Conflicts
Pulling Changes
When someone else pushes changes:
# Standard pull (creates merge commit)
git pull
# Rebase pull (cleaner history, no merge commit)
git pull -r
Merge Conflicts
When Git can’t automatically merge changes:
- Git marks conflicted files
- Manually edit files to resolve conflicts
- Stage resolved files:
git add conflicted_file
- Continue rebase:
git rebase --continue
- Push changes:
git push
Pull/Merge Requests
Essential for code review and collaboration:
- Purpose: Request to merge one branch into another
- Process: Create → Review → Approve → Merge
- Benefits: Code review, discussion, quality control
Managing Files
.gitignore
Exclude files/directories from version control:
# Create .gitignore file
echo ".idea/" >> .gitignore
echo "*.log" >> .gitignore
# Remove already tracked files
git rm -r --cached .idea
git commit -m "Remove .idea from tracking"
Temporary Storage
# Temporarily store changes
git stash
# Retrieve stashed changes
git stash pop
Viewing History and Navigation
# View commit history with graph
git log --oneline --graph
# Go to specific commit (detached HEAD)
git checkout commit_hash
# Return to latest commit
git checkout branch_name
Undoing Changes
Local Changes (Use Carefully)
# Undo last commit, keep changes in working directory
git reset --soft HEAD~1
# Undo last commit, discard changes completely
git reset --hard HEAD~1
# Modify last commit (add changes or fix message)
git add .
git commit --amend
Remote Changes (When Working Alone)
# Remove commit from remote (dangerous!)
git reset --hard HEAD~1
git push --force
Safe Undoing (Team Environment)
# Create new commit that undoes previous commit
git revert commit_hash
Rule of Thumb: Use reset when working alone, use revert when working in a team.
Branch Merging
# Merge source_branch into current branch
git checkout target_branch
git merge source_branch
Key Takeaways for DevOps
- Infrastructure as Code: Your Terraform files, Ansible playbooks, and Kubernetes manifests should live in Git
- Automation Scripts: Python scripts, shell scripts, and other automation tools need version control
- CI/CD Integration: Build systems need to interact with Git repositories
- Collaboration: Even infrastructure changes need code review through pull requests
- Rollback Capability: Git history allows you to rollback infrastructure changes safely
Best Practices
- Write descriptive commit messages
- Commit small, related changes together
- Pull frequently to stay in sync
- Don’t push directly to main/master branch
- Use meaningful branch names:
feature/user-auth, bugfix/memory-leak
- Set up proper
.gitignore files for your projects
- Use
git pull -r to maintain clean history
Git Commands Cheat Sheet
Git Configuration
| Command | Description |
|---|
git config --global user.name <name> | Define the author name to be used for all commits by the current user |
git config --global user.email <email> | Define the author email to be used for all commits by the current user |
git config --global alias.<alias-name> <git-command> | Create shortcut for a Git command. E.g. alias glog “log —graph —oneline” |
git config --system core.editor <editor> | Set text editor used by commands for all users on the machine |
git config --global --edit | Open the global configuration file in a text editor for manual editing |
Git Basics
| Command | Description |
|---|
git init <directory> | Create empty Git repo in specified directory. Run with no arguments to initialize the current directory as a git repository |
git clone <repo> | Clone repo located at <repo> onto local machine. Original repo can be located on the local filesystem or on a remote machine via HTTP or SSH |
git add <directory> | Stage all changes in <directory> for the next commit. Replace <directory> with a <file> to change a specific file |
git commit -m "<message>" | Commit the staged snapshot, but instead of launching a text editor, use <message> as the commit message |
git status | List which files are staged, unstaged, and untracked |
git log | Display the entire commit history using the default format. For customization see additional options |
git diff | Show unstaged changes between your index and working directory |
Git Branches
| Command | Description |
|---|
git branch | List all of the branches in your repo. Add a <branch> argument to create a new branch with the name <branch> |
git checkout -b <branch> | Create and check out a new branch named <branch>. Drop the -b flag to checkout an existing branch |
git merge <branch> | Merge <branch> into the current branch |
Git Log Options
| Command | Description |
|---|
git log --limit=<limit> | Limit number of commits by <limit>. E.g. “git log -5” will limit to 5 commits |
git log --oneline | Condense each commit to a single line |
git log -p | Display the full diff of each commit |
git log --stat | Include which files were altered and the relative number of lines that were added or deleted from each of them |
git log --author="<pattern>" | Search for commits by a particular author |
git log --grep="<pattern>" | Search for commits with a commit message that matches <pattern> |
git log <since>..<until> | Show commits that occur between <since> and <until>. Args can be a commit ID, branch name, HEAD, or any other kind of revision reference |
git log -- <file> | Only display commits that have the specified file |
git log --graph --decorate | —graph flag draws a text based graph of commits on left side of commit msgs. —decorate adds names of branches or tags of commits shown |
Git Diff
| Command | Description |
|---|
git diff HEAD | Show difference between working directory and last commit |
git diff --cached | Show difference between staged changes and last commit |
Git Reset
| Command | Description |
|---|
git reset | Reset staging area to match most recent commit, but leave the working directory unchanged |
git reset --hard | Reset staging area and working directory to match most recent commit and overwrites all changes in the working directory |
git reset <commit> | Move the current branch tip backward to <commit>, reset the staging area to match, but leave the working directory alone |
git reset --hard <commit> | Same as previous, but resets both the staging area & working directory to match. Deletes uncommitted changes, and all commits after <commit> |
Git Rebase
| Command | Description |
|---|
git rebase -i <base> | Interactively rebase current branch onto <base>. Launches editor to enter commands for how each commit will be transferred to the new base |
Git Pull
| Command | Description |
|---|
git pull --rebase <remote> | Fetch the remote’s copy of current branch and rebases it into the local copy. Uses git rebase instead of merge to integrate the branches |
Git Push
| Command | Description |
|---|
git push <remote> --force | Forces the git push even if it results in a non-fast-forward merge. Do not use the —force flag unless you’re absolutely sure you know what you’re doing |
git push <remote> --all | Push all of your local branches to the specified remote |
git push <remote> --tags | Tags aren’t automatically pushed when you push a branch or use the —all flag. The —tags flag sends all of your local tags to the remote repo |
Undoing Changes
| Command | Description |
|---|
git revert <commit> | Create new commit that undoes all of the changes made in <commit>, then apply it to the current branch |
git reset <file> | Remove <file> from the staging area, but leave the working directory unchanged. This unstages a file without overwriting any changes |
git clean -n | Shows which files would be removed from working directory. Use the -f flag in place of the -n flag to execute the clean |
Rewriting Git History
| Command | Description |
|---|
git commit --amend | Replace the last commit with the staged changes and last commit combined. Use with nothing staged to edit the last commit’s message |
git rebase <base> | Rebase the current branch onto <base>. <base> can be a commit ID, branch name, a tag, or a relative reference to HEAD |
git reflog | Show a log of changes to the local repository’s HEAD. Add —relative-date flag to show date info or —all to show all refs |
Remote Repositories
| Command | Description |
|---|
git remote add <name> <url> | Create a new connection to a remote repo. After adding a remote, you can use <name> as a shortcut for <url> in other commands |
git fetch <remote> <branch> | Fetches a specific <branch> from the repo. Leave off <branch> to fetch all remote refs |
git pull <remote> | Fetch the specified remote’s copy of current branch and immediately merge it into the local copy |
git push <remote> <branch> | Push the branch to <remote>, along with necessary commits and objects. Creates named branch in the remote repo if it doesn’t exist |