Estimated Time: 5 minutes
This guide will let you experience what it's like to develop with Kelda. We will be working with a real-world, open source, microservices application called Magda. We will deploy a development instance of Magda, fix a bug, and see our local changes take effect immediately on the development server. Let's jump in.
Run the following command to download and install Kelda.
curl -fsSL 'https://kelda.io/install.sh' | sh
Download the Kelda examples repository
This repository contains the source code and Kelda config for Magda.
git clone https://github.com/kelda-inc/examples
Configure Kelda to work on the Magda project
The following command creates a file that's required for the
keldacommands to work.
Most users can just use the defaults by hitting [Enter] for each prompt.
In the root directory of the examples repository, run:
If the command succeeded, you should see something like:
Wrote config to /Users/kevin/.kelda.yaml
Kelda maintains a public cluster for demo purposes. If you've already setup a Kelda cluster, just omit the
Start Kelda by running
kelda dev ./magda/magda-web-server
kelda devprocess should not be killed during development.
It's needed to sync local changes, and to keep the tunnels open.
If you accidentally kill it, you can restart it by re-running the
This command boots Magda, syncs the files in the
magda-web-serverdirectory, and creates tunnels for accessing the application.
Wait for all the services to become
Ready. The first boot may take several minutes because the Docker images need to be pulled.
View the Bug
Open http://localhost:8080 in your browser. You should see a website with a search box.
Try searching for "Australia" -- a red error message should pop up on the bottom right portion of the screen complaining about a SyntaxError in JSON.
Fix the SyntaxError bug
Fix this bug by editing your local copy of
magda/magda-web-server/src/index.js, and replacing
v0on line 104.
You will notice that Kelda will automatically sync your change and restart the affected containers. The Development Status portion of the Kelda terminal application informs you of all of the changes that are occurring in real time.
If you refresh the page in your browser, and then perform a new search, you should see the
SyntaxErrorgo away, and search results begin to appear.
View service logs
kelda logs allows you to inspect the logs of any running service in your cluster.
In your terminal, run
kelda logs gatewayto inspect all of the requests that have been made to your
gatewayservice since you began this guide.
SSH into a service
kelda ssh allows you to remotely access any service in your cluster.
In your terminal, run
kelda ssh gateway. This will place you into a shell on the gateway service container running inside your Kubernetes cluster.
ps auxto see all of the currently running processes inside the gateway service container. The output should look something like this:
kelda ssh gateway # ps aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0.2 0.7 1220256 57016 ? Ssl 18:52 0:03 node /usr/src root 22 0.0 0.0 4344 776 ? Ss 19:13 0:00 sh root 30 0.0 0.0 17512 2080 ? R+ 19:14 0:00 ps aux
To exit the SSH session, run
kelda devby entering
Ctrl + cinto the terminal window where the Kelda CLI is running.
Delete your development namespace
kelda deleteto delete your development namespace so that it stops consuming resources in the remote cluster.
Congratulations! You've now seen how easy it is to use Kelda to make changes to your code base locally and instantly see them reflected in a Kubernetes cluster.
If you're interested in using Kelda for your own application, you should deploy Kelda on your own infrastructure next.