Stemcells
In order to manage BOSH stemcells in anynines-deployment, we've made stemcells
configurable via the IaaS config. We configure a list of stemcells in
iaas.stemcells
(see config/iaas-config.yml.example for an example).
This has the benefit of having all stemcells configured in one location and
having it referenced anywhere it's needed. It also allows to use one type of
stemcell in the services and another in the Service Instances. You can also use
ops files to configure a certain type of stemcells for a particular component.
This gives you a lot of control while preserving DRY
principles by using sensible defaults.
Currently, Ubuntu Jammy is the default stemcell for all services and Service Instances. This can be changed to any OS supported by anynines-deployment.
In general, Ubuntu Xenial and Ubuntu Bionic are no longer supported.
Currently supported stemcells
Currently, only the Ubuntu Jammy stemcell is supported on compatible CPIs.
We've tested the following versions on our test system:
Linux stemcells | Versions | Comment |
---|---|---|
Ubuntu Jammy | 1.866 | |
Ubuntu Bionic | 1.204 | Unsupported |
Ubuntu Xenial | 621.125 | Unsupported |
Changing the default stemcell
We use YAML anchors to create a reference to a particular stemcell and use that reference throughout the IaaS config file. Please find the string &a9s-stemcell-default in the IaaS config file (example: config/iaas-config.yml.example) and "move" the string (a so called YAML anchor) to another stemcell. You can also introduce a different stemcell below the stemcell that uses this YAML anchor and assign it the YAML anchor &a9s-stemcell-default. After that, the default stemcell will be the one you configured.
An example for your IaaS config:
iaas:
stemcells:
ubuntu-jammy: &a9s-stemcell-default
os: ubuntu-jammy
alias: ubuntu-jammy
version: "1.866"
url: https://storage.googleapis.com/bosh-aws-light-stemcells/1.866/light-bosh-stemcell-1.866.tgz
sha1: 26a1fc3946db58d4954175ffd542e6534a80c1e3
You can then reference such a stemcell like e.g.:
logme2_service:
stemcells:
service: *a9s-stemcell-default
If you want to use a different stemcell or even stemcell version in your service instances only, you can do so by using an Ops file. Please find an example in ops/replace-stemcell-template-uploader.yml You might have to create your own copy of that Ops file with the correct values for your setup.
Example IaaS config
The following YAML text is an example IaaS configuration. It introduces a stemcell (Ubuntu Jammy) and allows referring
to it by using a YAML anchor (&a9s-stemcell-default
.
iaas:
stemcells:
ubuntu-jammy: &a9s-stemcell-default
os: ubuntu-jammy
alias: ubuntu-jammy
version: 1.866
sha1: 26a1fc3946db58d4954175ffd542e6534a80c1e3
In order to refer to them, you can use a YAML alias:
iaas:
data_service:
stemcell: *a9s-stemcell-default
Once you introduced the anchors and an alias, you can refer to these stemcells in different ways:
stemcells:
- os: ((iaas.data_service.stemcells.service.os))
alias: ((iaas.data_service.stemcells.service.alias))
version: ((iaas.data_service.stemcells.service.version))
- name: jobname
vm_type: small
instances: 1
azs: [z1, z2, z3]
stemcell: ((iaas.data_service.stemcells.service.alias))
jobs:
- { name: jobname, release: jobrelease }
properties:
...