BOSH Linux Stemcell Builder

This repo contains tools for creating BOSH stemcells. A stemcell is a bootable disk image that is used as a template by a BOSH Director to create VMs.

Quick Start: Building a Stemcell Locally

export short_name="jammy"

git clone git@github.com:cloudfoundry/bosh-linux-stemcell-builder.git
cd bosh-linux-stemcell-builder
git checkout ubuntu-${short_name}
mkdir -p tmp
docker build \
   --platform linux/amd64 \
   --build-arg SYFT_VERSION=v1.42.3 \
   -t bosh/os-image-stemcell-builder:${short_name} \
   ci/docker/os-image-stemcell-builder/
docker run \
   --platform linux/amd64 \
   --privileged \
   -v "$(pwd):/opt/bosh" \
   --workdir /opt/bosh \
   --user=1000:1000 \
   -it \
   bosh/os-image-stemcell-builder:${short_name}

# You're now in the Docker container
pushd bosh-stemcell
  bundle install
popd

 # build OS image
bundle exec rake stemcell:build_os_image[ubuntu,${short_name},${PWD}/tmp/ubuntu_base_image.tgz]

 # build vSphere stemcell
bundle exec rake stemcell:build[vsphere,esxi,ubuntu,${short_name},${PWD}/tmp/ubuntu_base_image.tgz]

When building a vSphere stemcell, you must download VMware-ovftool-*.bundle and place it in the ci/docker/os-image-stemcell-builder/ directory before running docker build. See External Assets for download instructions.

OS image

An OS image is a tarball that contains a snapshot of an OS filesystem, including the libraries and system utilities needed by the BOSH agent; however, it does not contain the BOSH agent nor the virtualization tools: a subsequent Rake task adds the BOSH agent and a set of virtualization tools to the base OS image to produce a stemcell.

The OS Image should be rebuilt when you are making changes to the packages installed in the operating system or when making changes to the configuration of those packages.

export short_name="jammy"

bundle exec rake stemcell:build_os_image[ubuntu,${short_name},${PWD}/tmp/ubuntu_base_image.tgz]

The arguments to the stemcell:build_os_image rake task follow:

1. operating_system_name (ubuntu): identifies which type of OS to fetch. Determines which package repository and packaging tool will be used to download and assemble the files. Currently, only ubuntu is recognized.
2. operating_system_version (<short_name>): an identifier that the system may use to decide which release of the OS to download. Acceptable values depend on the operating system. For ubuntu, use <short_name>.
3. os_image_path (${PWD}/tmp/ubuntu_base_image.tgz): the path to write the finished OS image tarball to. If a file exists at this path already, it will be overwritten without warning.

Building a Stemcell

Rebuild the stemcell when you are making and testing BOSH-specific changes such as a new BOSH agent.

export short_name="jammy"
export build_number="0.0.8"

bundle exec rake stemcell:build[vsphere,esxi,ubuntu,${short_name},${PWD}/tmp/ubuntu_base_image.tgz,${build_number}]

The arguments to stemcell:build are:

1. infrastructure_name: Which IaaS you are producing the stemcell for. Determines which virtualization tools to package on top of the stemcell.
2. hypervisor_name: Depending on what the IAAS supports, which hypervisor to target:
   • aws → xen-hvm
   • azure → hyperv
   • google → kvm
   • openstack → kvm
   • vsphere → esxi
3. operating_system_name (ubuntu): Type of OS. Same as stemcell:build_os_image.
4. operating_system_version (<short_name>): OS release. Same as stemcell:build_os_image. Can optionally include a variant suffix (<short_name>-fips)
5. os_image_path (${PWD}/tmp/ubuntu_base_image.tgz): Path to base OS image produced in stemcell:build_os_image
6. build_number (0.0.8): Stemcell version. Pro-tip: take the version number of the most recent release and add one, e.g.: "0.0.7" → "0.0.8". If not specified, it will default to "0000".

The Resulting Stemcell

You can find the resulting stemcell in the tmp/ directory of the host, or in the /opt/bosh/tmp directory in the Docker container. Using the above example, the stemcell would be at tmp/bosh-stemcell-0.0.8-vsphere-esxi-ubuntu-<short_name>-go_agent.tgz. You can upload the stemcell to a vSphere BOSH Director:

export short_name="jammy"

bosh upload-stemcell tmp/bosh-stemcell-0.0.8-vsphere-esxi-ubuntu-${short_name}-go_agent.tgz

Testing

How to run tests for OS Images

The OS tests are meant to be run against the OS environment to which they belong. When you run the stemcell:build_os_image rake task, it will create a .raw OS image that it runs the OS specific tests against. You will need to run the rake task the first time you create your docker container, but everytime after, as long as you do not destroy the container, you should be able to run the specific tests.

To run the OS image tests in spec/os_image/ubuntu_spec.rb (assuming you've already built the OS image at the tmp/ubuntu_base_image.tgz and you're within the Docker container):

  export short_name="jammy"
  cd /opt/bosh/bosh-stemcell
  bundle install
  OS_IMAGE=/opt/bosh/tmp/ubuntu_base_image.tgz bundle exec rspec -fd spec/os_image/ubuntu_spec.rb

How to Run Tests for Stemcell

When you run the stemcell:build rake task, it will create a stemcell that it runs the stemcell-specific tests against. You will need to run the rake task the first time you create your docker container, but every time after, as long as you do not destroy the container, you should be able to run the specific tests:

cd /opt/bosh/bosh-stemcell; \
bundle install; \
STEMCELL_IMAGE=/mnt/stemcells/vsphere/esxi/ubuntu/work/work/vsphere-esxi-ubuntu.raw \
STEMCELL_WORKDIR=/mnt/stemcells/vsphere/esxi/ubuntu/work/work/chroot \
OS_NAME=ubuntu \
bundle exec rspec -fd --tag ~exclude_on_vsphere \
spec/os_image/ubuntu_spec.rb \
spec/stemcells/ubuntu_spec.rb \
spec/stemcells/go_agent_spec.rb \
spec/stemcells/vsphere_spec.rb \
spec/stemcells/stig_spec.rb \
spec/stemcells/cis_spec.rb

How to run tests for ShelloutTypes

In pursuit of more robustly testing, we wrote our testing library for stemcell contents, called ShelloutTypes.

The ShelloutTypes code has its own unit tests, but require root privileges and an ubuntu chroot environment to run. For this reason, we use the bosh/main-ubuntu-chroot docker image for unit tests. To run these unit tests locally, run:

cd /opt/bosh/bosh-stemcell
bundle install
OS_IMAGE=/opt/bosh/tmp/ubuntu_base_image.tgz bundle exec rake spec:shellout_types

How to run tests for BOSH Linux Stemcell Builder

The BOSH Linux Stemcell Builder code itself can be tested with the following command's:

cd /opt/bosh/bosh-stemcell
bundle install
bundle exec rake

Troubleshooting

If you find yourself debugging any of the above processes, here is what you need to know:

1. Most of the action happens in Bash scripts, which are referred to as stages, and can be found in stemcell_builder/stages/<stage_name>/apply.sh.
2. While debugging a particular stage that is failing, you can resume the process from that stage by adding resume_from=<stage_name> to the end of your bundle exec rake command. When a stage's apply.sh fails, you should see a message of the form Can't find stage '<stage>' to resume from. Aborting. so you know which stage failed and where you can resume from after fixing the problem. Please use caution as stages are not guaranteed to be idempotent.

Example usage:

```shell export short_name="jammy"

bundle exec rake stemcell:build_os_image[ubuntu,${short_name},${PWD}/tmp/ubuntu_base_image.tgz] resume_from=rsyslog_config ```

Pro Tips

• If the OS image has been built and so long as you only make test case modifications you can rerun the tests (without rebuilding OS image). Details in section How to run tests for OS Images
• If the Stemcell has been built, and you are only updating tests, you do not need to re-build the stemcell. You can simply rerun the tests - without rebuilding Stemcell. Details in section How to run tests for Stemcell
• It's possible to verify OS/Stemcell changes without making a deployment using the stemcell. For a vSphere-specific Ubuntu stemcell, the filesystem is available at /mnt/stemcells/vsphere/esxi/ubuntu/work/work/chroot

External Assets

The installer for ovftool can be found at: - https://developer.broadcom.com/tools/open-virtualization-format-ovf-tool/latest.

The ovftool installer for linux must be copied into os-image-stemcell-builder next to the Dockerfile before building the Docker image. If not you will see an error similar to:

ADD failed: failed to compute cache key: "/VMware-ovftool-4.4.3-18663434-lin.x86_64.bundle": not found

Rebuilding the Docker Image

The Docker image is published to bosh/os-image-stemcell-builder. You will need the ovftool installer present in ci/docker/os-image-stemcell-builder/.

Rebuild the container with:

export short_name="jammy"

docker build \
    --platform linux/amd64 \
    --build-arg BASE_IMAGE="ubuntu:${short_name}" \
    --build-arg META4_CLI_URL="https://github.com/dpb587/metalink/releases/download/v0.5.0/meta4-0.5.0-linux-amd64" \
    --build-arg SYFT_CLI_URL="https://github.com/anchore/syft/releases/download/v1.42.3/syft_1.42.3_linux_amd64.tar.gz" \
    --build-arg YQ_CLI_URL="https://github.com/mikefarah/yq/releases/download/v4.52.5/yq_linux_amd64" \
    --build-arg RUBY_INSTALL_URL="https://github.com/postmodern/ruby-install/releases/download/v0.10.2/ruby-install-0.10.2.tar.gz" \
    --build-arg RUBY_VERSION="$(cat .ruby-version)" \
    --build-arg GEM_HOME="/usr/local/bundle" \
    --build-arg OVF_TOOL_INSTALLER="VMware-ovftool-4.4.3-18663434-lin.x86_64.bundle" \
    --build-arg OVF_TOOL_INSTALLER_SHA1="6c24e473be49c961cfc3bb16774b52b48e822991" \
    -t bosh/os-image-stemcell-builder:${short_name} \
    ci/docker/os-image-stemcell-builder/

CI Infrastructure

Docker Images and VMware ovftool

When creating a new LTS stemcell you will need to create a folder and upload the appropriate ovftool to the GCP bucket bosh-vmware-ovftool:

gsutil cp MY_OVFTOOL_FILE gs://bosh-vmware-ovftool/MY_OS/

Example:

export short_name="jammy"

gsutil cp VMware-ovftool-4.4.3-18663434-lin.x86_64.bundle gs://bosh-vmware-ovftool/${short_name}/

GCP

The stemcell pipelines currently run on a Concourse instance configured here:

• https://github.com/cloudfoundry/concourse-infra-for-fiwg

Concourse publishes its artifacts to GCS.

Create Buckets

export gcp_region="europe-west4"

gsutil mb -l "${gcp_region}"  gs://bosh-aws-light-stemcells
gsutil mb -l "${gcp_region}"  gs://bosh-aws-light-stemcells-candidate

gsutil mb -l "${gcp_region}"  gs://bosh-gce-light-stemcell-ci-terraform-state

gsutil mb -l "${gcp_region}"  gs://bosh-gce-light-stemcells
gsutil mb -l "${gcp_region}"  gs://bosh-gce-light-stemcells-candidate
gsutil mb -l "${gcp_region}"  gs://bosh-gce-raw-stemcells-new

gsutil mb -l "${gcp_region}"  gs://bosh-core-stemcells
gsutil mb -l "${gcp_region}"  gs://bosh-core-stemcells-candidate
gsutil mb -l "${gcp_region}"  gs://bosh-os-images
gsutil mb -l "${gcp_region}"  gs://bosh-stemcell-triggers

Make Buckets Publicly Readable

gsutil iam ch allUsers:objectViewer gs://bosh-os-images

gsutil iam ch allUsers:objectViewer gs://bosh-core-stemcell
gsutil iam ch allUsers:objectViewer gs://bosh-core-stemcells-candidate

gsutil iam ch allUsers:objectViewer gs://bosh-aws-light-stemcells
gsutil iam ch allUsers:objectViewer gs://bosh-aws-light-stemcells-candidate

gsutil iam ch allUsers:objectViewer gs://bosh-gce-light-stemcells
gsutil iam ch allUsers:objectViewer gs://bosh-gce-light-stemcells-candidate

Set Versioning

gsutil versioning set on gs://bosh-stemcell-triggers

Configure Firewall

The default-allow-internal firewall rule should allow the subnet 10.0.0.0/8 on all ports:

gcloud compute firewall-rules update default-allow-internal --source-ranges 10.0.0.0/8

Create Integration Networks

Create a stemcell-builder-integration-${subnet_int} subnetworks need by BATs tests. Each stemcell line should get its own subnet corresponding to its subnet_int equal to the two digit release year. For example release year 2010 would have subnet_int="10".

Example per ci/pipeline-vars.yml:

---
stemcell_details:
  # ... snip
  subnet_int: "10" #! use last two digits of release year: ex 2010 -> 10
  # ... snip

Would mean creating the following subnet in GCP:

# branch: ubuntu-${short_name}
export subnet_int="10"

gcloud compute networks subnets create --network default \
  --range "10.100.${subnet_int}.0/24" "stemcell-builder-integration-${subnet_int}"

AWS

Concourse will want to publish its artifacts. Create IAM users with the appropriate policy files:

• For stemcells: use the bosh-core-stemcells IAM policy. Create buckets for stemcells, then give them a public-read policy.
• For OS images: use the bosh-os-images IAM policy. Create buckets for OS images, then give them a public-read policy.

OS Images Pipeline Migration

When switching from the old pipeline to the new one, don't forget to:

• update pipeline.yml and change the bucket from bosh-os-images-dev to whatever the public bucket should be
• update the tasks YAML to point to tasks in the os-images directory
• rename this directory from new