whitemike889 / sysadmin

System administration tools

OONI sysadmin

In here live all the tools and scripts related to administering the infrastructure that are part of OONI.

Getting started

It is recommended you use a python virtualenv to install ansible and dnspython.

Once you activate the virtualenv you can install the correct version of ansible and dnspython with:

pip install ansible==2.8.3 dnspython==1.15.0

Ansible roles

It is required for all OONI team to run the same ansible version to minimise compatibility issues. All playbooks should include ansible-version.yml at the beginning of the playbook, by including:

---
- import_playbook: ansible-version.yml

If you need some python packages only for ansible module to work and don't need it in system-wide pip repository, then you should put these modules in separate virtual environment and set proper ansible_python_interpreter for the play. See docker_py role and grep for /root/venv for examples.

If you need to store secrets in repository then store them as vaults using ansible/vault script as a wrapper for ansible-vault. Store encrypted variables with vault_ prefix to make world a more grepable place and link location of the variable using same name without prefix in corresponding vars.yml. scripts/ansible-syntax-check checks links between vaults and plaintext files during Travis build. ansible/play wrapper for ansible-playbook will execute a playbook with proper vault secret and inventory.

SSH Config

You should configure your ~/.ssh/config with the following:

Ciphers aes128-ctr,aes256-ctr,aes128-cbc,aes256-cbc
IdentitiesOnly yes
ServerAliveInterval 120
UserKnownHostsFile ~/.ssh/known_hosts ~/PATH/TO//ooni/sysadmin/ext/known_hosts

Replace ~/PATH/TO//ooni/sysadmin/ext/known_hosts to where you have cloned the ooni/sysadmin repo. This will ensure you use the host key fingeprints from this repo instead of just relying on TOFU.

You probably also want to add:

host *.ooni.io
  user USERNAME
  identityfile ~/.ssh/id_rsa

host *.ooni.nu
  user USERNAME
  identityfile ~/.ssh/id_rsa

You should replace USERNAME with your username from adm_login.

On macOS you may want to also add:

host *
    UseKeychain yes

To use the Keychain to store passwords.

M-Lab deployment

M-Lab deployment process.

Upgrading OONI infrastructure

ooni-backend pitfalls

• Ensure that the HS private keys of bouncer and collector are in right PATH (collector/private_key , bouncer/private_key).
• Set the bouncer address in bouncer.yaml to the correct HS address.
• ooni-backend will not generate missing directories and fail to start

Running a short ooni-probe test will ensure that the backend has been successfully upgraded, an example test:

ooniprobe --collector httpo://CollectorAddress.onion blocking/http_requests \
--url http://ooni.io/

New host HOWTO

• come up with a name for $name.ooni.tld using DNS name policy
• create a VM to allocate IP address
• create A record for the domain name in namecheap web UI (API is hell)
• fetch external inventory with ./play ext-inventory.yml, it'll create a git commit
• add $name.ooni.tld to location tags section of inventory file, git-commit it
• write firewall rules to templates/iptables.filter.part/$name.ooni.tld if needed, git-commit it
• bootstrap VM with ./play dom0-bootstrap.yml -l $name.ooni.tld
• update Prometheus with ./play deploy-prometheus.yml -t prometheus-conf
• check inventory sanity with ./play inventory-check.yml (everything should be ok, no changes, no failures), update inventory-check.yml with new checksum, git-commit it
• git push those commits

DNS name policy

Public HTTP services are named ${service}.ooni.org or ${service}.ooni.io (legacy). Public means that it's part of some external system we can't control: published APP or MK versions, web URLs and so on. Public names should not be used as an inventory_hostname to ease migration.

VMs should have FQDN like ${location}-${name}-${number}.ooni.org. VMs can provide one or more public-facing services that can change over time. The name should be as descriptive as possible e.g. the type of services or the most important service being run.

Various legacy names should be cleaned up during re-deploying VMs with newer base OS version.

Rename host HOWTO

First, try hard to avoid renaming hosts. It's pain:

• inventory_hostname is stamped in Prometheus SSL certificates
• inventory_hostname is stamped as FQDN inside of firewall rules
• inventory_hostname is stamped as filename for firewall rules
• hostname is stamped in /etc/hosts on the host
• hostname is stamped as kernel.hostname on the host
• some applications use hostname as configuration value, e.g. MongoDB

But re-deploying is not also an options sometimes due to GH platform limitations. So...

• use New host HOWTO as a checklist to keep in mind
• on-rename tag can save some time while running dom0-bootstrap: ./play dom0-bootstrap.yml -t on-rename -l $newname.ooni.tld
• grep ooni/sysadmin for inventory_hostname, $oldname, $newname (NB: not just oldname.ooni.tld, short name may be used somewhere as well)

PostgreSQL replica bootstrap

pg_basebackup is nice, but does not support network traffic compression out of box and has no obvious way to resume interrupted backup. rsync solves that issue, but it needs either WAL archiving (to external storage) to be configured or wal_keep_segments to be non-zero, because otherwise WAL logs are rotated ASAP (min_wal_size and max_wal_size do not set amount of WAL log available to reader, these options set amount of disk space allocated to writer!). Also replication slot may reserve WAL on creation, but beware, it postpones WAL reservation till replica connection by default.

pg_start_backup() + rsync -az --exclude pg_replslot --exclude postmaster.pid --exclude postmaster.opts is a way to go. And, obviously, don't exclude pg_wal (aka pg_xlog) if neither WAL archiving nor replication slot is not set up.

And don't forget to revoke authorized_keys if SSH was used for rsync!

You may also want to bootstrap the replica from MetaDB snapshot in S3 and switch it to streaming replication afterwards.

Updating firewall rules

If you need to update the firewalling rules, because you added a new host to the have_fw group or you changed the hostname of a host, you should edit the file templates/iptables.filter.part/$HOSTNAME and then run:

./play dom0-bootstrap.yml -t fw