Arch Infrastructure

This repository contains the complete collection of ansible playbooks and roles for the Arch Linux infrastructure.

It also contains git submodules so you have to run git submodule update --init --recursive after cloning or some tasks will fail to run.

Requirements

Install these packages:

• terraform

Instructions

All systems are set up the same way. For the first time setup in the Hetzner rescue system, run the provisioning script: ansible-playbook playbooks/tasks/install-arch.yml -l $host. The provisioning script configures a sane basic systemd with sshd. By design, it is NOT idempotent. After the provisioning script has run, it is safe to reboot.

Once in the new system, run the regular playbook: HCLOUD_TOKEN=$(misc/get_key.py misc/vault_hetzner.yml hetzner_cloud_api_key) ansible-playbook playbooks/$hostname.yml. This playbook is the one regularity used for administrating the server and is entirely idempotent.

When adding a new machine you should also deploy our SSH known_hosts file and update the SSH hostkeys file in this git repo. For this you can simply run the playbooks/tasks/sync-ssh-hostkeys.yml playbook and commit the changes it makes to this git repository. It will also deploy any new SSH host keys to all our machines.

Note about Ansible dynamic inventories

We use a dynamic inventory script in order to automatically get information for all servers directly from hcloud. You don't really have to do anything to make this work but you should keep in mind to NOT add hcloud servers to hosts! They'll be available automatically.

Note about first time certificates

The first time a certificate is issued, you'll have to do this manually by yourself. First, configure the DNS to point to the new server and then run a playbook onto the server which includes the nginx role. Then on the server, it is necessary to run the following once:

certbot certonly --email webmaster@archlinux.org --agree-tos --rsa-key-size 4096 --renew-by-default --webroot -w /var/lib/letsencrypt/ -d <domain-name>

Note that some roles already run this automatically.

Note about packer

We use packer to build snapshots on hcloud to use as server base images. In order to use this, you need to install packer and then run

packer build -var $(misc/get_key.py misc/vault_hetzner.yml hetzner_cloud_api_key env) packer/archlinux.json

This will take some time after which a new snapshot will have been created on the primary hcloud archlinux project.

Note about terraform

We use terraform to provision a part of the infrastructure on hcloud. The very first time you run terraform on your system, you'll have to init it:

terraform init -backend-config="conn_str=postgres://terraform:$(misc/get_key.py group_vars/all/vault_terraform.yml vault_terraform_db_password)@state.cloud.archlinux.org"

After making changes to the infrastructure in archlinux.fg, run

terraform plan

This will show you planned changes between the current infrastructure and the desired infrastructure. You can then run

terraform apply

to actually apply your changes.

We store terraform state on a special server that is the only hcloud server NOT managed by terraform so that we do not run into a chicken-egg problem. The state server is assumed to just exist so in an unlikely case where we have to entirely redo this infrastructure, the state server would have to be manually set up.

Note about opendkim

The opendkim DNS data has to be added to DNS manually. The roles verifies that the DNS is correct before starting opendkim.

The file that has to be added to the zone is /etc/opendkim/private/$selector.txt.

Putting a service in maintenance mode

Most web services with a nginx configuration, can be put into a maintenance mode, by running the playbook with a maintenance variable:

ansible-playbook -e maintenance=true playbooks/<playbook.yml>

This also works with a tag:

ansible-playbook -t <tag> -e maintenance=true playbooks/<playbook.yml>

As long as you pass the maintenance variable to the playbook run, the web service will stay in maintenance mode. As soon as you stop passing it on the command line and run the playbook again, the regular nginx configuration should resume and the service should accept requests by the end of the run.

Passing maintenance=false, will also prevent the regular nginx configuration from resuming, but will not put the service into maintence mode.

Keep in mind that passing the maintenance variable to the whole playbook, without any tag, will make all the web services that have the maintenance mode in them, to be put in maintenance mode. Use tags to affect only the services you want.

Documentation on how to add the maintenance mode to a web service is inside docs/maintenance.txt

Finding servers requiring security updates

Arch-audit can be used to find servers in need of updates for security issues.

ansible all -a "arch-audit -u"

Updating servers

The following steps should be used to update our managed servers:

• pacman -Syu
• manually update the kernel, since it is in IgnorePkg by default
• sync
• checkservices
• reboot

Servers

vostok

Services

• backups

orion

Services

• repos/sync (repos.archlinux.org)
• sources (sources.archlinux.org)
• archive (archive.archlinux.org)
• torrent tracker hefurd (tracker.archlinux.org)

apollo

Services

• bbs (bbs.archlinux.org)
• wiki (wiki.archlinux.org)
• aur (aur.archlinux.org)
• flyspray (bugs.archlinux.org)
• mailman
• planet (planet.archlinux.org)
• bugs (bugs.archlinux.org)
• archweb
• patchwork
• projects (projects.archlinux.org)

soyuz

Services

• build server (pkgbuild.com)
• releng
• sogrep
• /~user/ webhost
• irc bot (phrik)
• matrix
• docker images
• arch boxes (packer)

dragon

Services

• build server (pkgbuild.com)
• sogrep

state.cloud.archlinux.org

Services:

• postgres server for terraform state

quassel.archlinux.org

Services:

• quassel core

Ansible repo workflows

Replace vault password and change vaulted passwords

• Generate a new key and save it as ./new-vault-pw: pwgen -s 64 1 > new-vault-pw
• for i in $(ag ANSIBLE_VAULT -l); do ansible-vault rekey --new-vault-password-file new-vault-pw $i; done
• Change the key in misc/vault-password.gpg
• rm new-vault-pw