ceph-devstack

A tool for testing Ceph locally using nested rootless podman containers

Overview

ceph-devstack is a tool that can deploy and manage containerized versions of teuthology and its associated services, to test Ceph (or just teuthology) on your local machine. It lets you avoid:

• Accessing Ceph's Sepia lab
• Needing dedicated storage devices to test Ceph OSDs

It is currently under active development and has not yet had a formal release.

Supported Operating Systems

☑︎ CentOS 9.Stream should work out of the box

☑︎ CentOS 8.Stream mostly works - but has not yet passed a Ceph test

☐ A recent Fedora should work but has not been tested

☒ Ubuntu does not currently ship a new enough podman

☒ MacOS will require special effort to support since podman operations are done inside a VM

Requirements

• A supported operating system
• podman 4.0+ using the crun runtime.
  • On CentOS 8, modify /etc/containers/containers.conf to set the runtime
• Linux kernel 5.12+, or 4.15+ and fuse-overlayfs
• cgroup v2
  • On CentOS 8, see ./docs/cgroup_v2.md
• podman's DNS plugin, from the podman-plugins package
• A user account that has sudo access and also is a member of the disk group
• The following sysctl settings:
  • fs.aio-max-nr=1048576
  • kernel.pid_max=4194304
• If using SELinux in enforcing mode:
  • setsebool -P container_manage_cgroup=true
  • setsebool -P container_use_devices=true

ceph-devstack doctor will check the above and report any issues.

Setup

sudo usermod -a -G disk $(whoami)  # and re-login afterward
git clone -b ceph-devstack https://github.com/ceph/teuthology/
cd teuthology && ./bootstrap
python3 -m venv venv
source ./venv/bin/activate
python3 -m pip install git+https://github.com/zmc/ceph-devstack.git

Configuration

ceph-devstack 's default configuration is here. It can be extended by placing a file at ~/.config/ceph-devstack/config.yml or by using the --config-file flag.

ceph-devstack show-conf will output the current configuration.

As an example, the following configuration will use a local image for paddles with the tag TEST; it will also create ten testnode containers; and will build its teuthology container from the git repo at ~/src/teuthology:

containers:
  paddles:
    image: localhost/paddles:TEST
  testnode:
    count: 10
  teuthology:
    repo: ~/src/teuthology

Usage

By default, pre-built container images are pulled from quay.io/ceph-infra. The images can be overridden via the config file. It's also possible to build images from on-disk git repositories.

First, you'll want to pull all the images:

ceph-devstack pull

Optional: If building any images from repos:

ceph-devstack build

Next, you can start the containers with:

ceph-devstack start

Once everything is started, a message similar to this will be logged:

View test results at http://smithi065.front.sepia.ceph.com:8081/

This link points to the running Pulpito instance. Test archives are also stored in the --data-dir (default: ~/.local/share/ceph-devstack).

To watch teuthology's output, you can:

podman logs -f teuthology

If you want testnode containers to be replaced as they are stopped and destroyed, you can:

ceph-devstack watch

When finished, this command removes all the resources that were created:

ceph-devstack remove

Specifying a Test Suite

By default, we run the teuthology:no-ceph suite to self-test teuthology. If we wanted to test Ceph itself, we could use the orch:cephadm:smoke-small suite:

export TEUTHOLOGY_SUITE=orch:cephadm:smoke-small

It's possible to skip the automatic suite-scheduling behavior:

export TEUTHOLOGY_SUITE=none

Using testnodes from an existing lab

If you need to use "real" testnodes and have access to a lab, there are a few additonal steps to take. We will use the Sepia lab as an example below:

To give the teuthology container access to your SSH private key (via podman secret):

export SSH_PRIVKEY_PATH=$HOME/.ssh/id_rsa

To lock machines from the lab:

ssh teuthology.front.sepia.ceph.com
~/teuthology/virtualenv/bin/teuthology-lock \
  --lock-many 1 \
  --machine-type smithi \
  --desc "teuthology dev testing"

Once you have your machines locked, you need to provide a list of their hostnames and their machine type:

export TEUTHOLOGY_TESTNODES="smithiXXX.front.sepia.ceph.com,smithiYYY.front.sepia.ceph.com"
export TEUTHOLOGY_MACHINE_TYPE="smithi"