Gandalf

To enable application deployment using git, tsuru uses Gandalf to manage Git repositories used to push applications to. It’s also responsible for setting hooks in these repositories which will notify the tsuru API when a new deploy is made. For more details check Gandalf Documentation.

Note

Gandalf is only required if you want to be able to deploy using git push, without it you can still deploy applications using tsuru app-deploy.

Gandalf will store and manage all Git repositories and SSH keys, as well as users. When user runs a git push, the communication happens directly between the user host and the Gandalf host, and Gandalf will notify tsuru the new deployment using a git hook.

Installing

Let’s start adding the repositories for tsuru which contain the Gandalf package.

deb:

$ curl -s https://packagecloud.io/install/repositories/tsuru/stable/script.deb.sh | sudo bash
$ sudo apt-get install gandalf-server

rpm:

$ curl -s https://packagecloud.io/install/repositories/tsuru/stable/script.rpm.sh | sudo bash
$ sudo yum install gandalf-server

For more details, check packagecloud.io documentation.

A deploy is executed in the git push. In order to get it working, you will need to add a pre-receive hook. tsuru comes with one pre-receive hook, but you can create your own.

Then you will need to configure Gandalf, install the pre-receive hook and start Gandalf. .. highlight:: bash

sudo mkdir -p /home/git/bare-template/hooks
sudo curl https://raw.githubusercontent.com/tsuru/tsuru/main/misc/git-hooks/pre-receive -o /home/git/bare-template/hooks/pre-receive
sudo chmod +x /home/git/bare-template/hooks/pre-receive
sudo chown -R git:git /home/git/bare-template

In the /etc/gandalf.conf file, remove the comment from the line “template: /home/git/bare-template” and from the line “database”, so it looks like that:

database:
  url: <your-mongodb-server>:27017
  name: gandalf

git:
  bare:
    location: /var/lib/gandalf/repositories
    template: /home/git/bare-template

Then start gandalf:

sudo start gandalf-server

Configuring tsuru to use Gandalf

In order to use Gandalf, you need to change tsuru.conf accordingly:

1. Define “repo-manager” to use “gandalf”;
2. Define “git:api-server” to point to the API of the Gandalf server (example: “http://localhost:8000”);

For more details, please refer to the configuration page.

Token for authentication with tsuru API

There is one last step in configuring Gandalf. It involves generating an access token so that the hook we created can access the tsuru API. To do so, we need to export t wo extra environment variables to the git user, which will run our deploy hooks, the URL to our API server and a generated token.

First step is to generate a token in the machine where the API server is installed:

$ tsurud token
fed1000d6c05019f6550b20dbc3c572996e2c044

Now you have to go back to the machine you installed Gandalf, and run this:

$ cat | sudo tee -a /home/git/.bash_profile <<EOF
export TSURU_HOST=http://<your-tsuru-api-addr>:8080
export TSURU_TOKEN=fed1000d6c05019f6550b20dbc3c572996e2c044
EOF

Adding Gandalf to an already existing tsuru cluster

In the case of an old tsuru cluster running without Gandalf, users and applications registered in tsuru won’t be available in the newly created Gandalf server, or both servers may be out-of-sync.

When Gandalf is enabled, administrators of the cloud can run the tsurud gandalf-sync command.

Managing SSH public keys

In order to be able to send git pushes to the Git server users need to have their key registered in Gandalf.