This section mentions features (suspending, tagging, and registry push/pull) which are not available with a free Anka Develop license.

When using Anka to create a VM, it’s best to think of the result as a VM “Template”. To create a Template, you’ll use the Anka CLI’s create command or Anka UI with any macOS installer .app file.

After a VM Template is created, you’ll have a clean macOS installation to play with and you can use anka view and/or anka run commands to install dependencies and software you need inside of the VM, or just configure it to your liking.

An example bash script that shows how to use anka run to install dependencies.

Once the system/Template is configured how you want it, you have two options:

1. Stop the VM Template: anka stop {templateName}
2. Suspend the VM Template: anka suspend {templateName}

With option 1, you are issuing a full shutdown – similar to hitting the power button on your physical machine – and therefore have to wait the full boot time for the VM to start back up. This usually takes 20 to 30 seconds.

With option 2, you can save the state of the VM/memory to a file which can then be used to start the VM almost instantly. However, these files that contain the state are several GBs in size and shouldn’t be used if your hosts are limited on disk space. Stopped Big Sur VMs are ~19GB, but can be more than 30GBs depending on the amount of memory given to the VM.

It’s very important that when you suspend from a started state the VM has fully booted and logged into a user. If you don’t, the VM may be frozen or fail to boot. You can script this using anka run {VMTemplateName} sleep 60 or manually check with anka view to ensure it’s in a good state.

Once you’ve chosen to stop or suspend the VM Template, you can then push the Template to your Anka Build Cloud Registry using anka registry push and set a Tag. Or, use anka registry push -l {vmNameOrUUID} -t {tag} to only create the Tag locally (useful if you don’t have a registry yet and want to quickly switch between Tags/dependencies locally while testing).

Important: When you start a VM and make changes, your changes are added to a new layer/file on top of the existing ones. This means that when you modify a Template or Tag, then push to the registry, or even pull down a new Template or Tag to an Anka Node, you’re sharing existing layers and saving disk space and bandwidth. It’s important to think about which clone/tagging/layering approach is best for you and your company. Also, each Start of a VM will cause higher disk usage/size of the Template files, even if you delete the older versions of your dependencies inside before installing the new. It’s best to delete/revert a tag or Template and clone a fresh one when you need to upgrade dependencies.

Once a Template is created, and Tag assigned to it, you can now create other Templates/Tags. Fortunately, Anka allows you to build Templates on top of each other and share the underlying files between them, cutting down on the disk space requirements. This makes switching between dependencies super easy, and also saves on bandwidth necessary to download/pull down TemplateB if layers from the sister, TemplateC, already exist on the machine.

You have two options to create Templates from Templates:

1. Use anka clone {sourceTemplate} {newTemplate} (recommended): The new cloned Template will have no Tags, but will link to the layers/contents from the previous Template and active Tag’s state. No new disk space will be used until you start and make changes.
2. Use anka clone --copy {sourceTemplate} {newTemplate}: The new cloned Template will have no Tags, and will copy all of the parent Template’s layers into a single file (flattening). This doubles the amount of disk space used.

When creating a clone without --copy, deletion of the first Template will not delete the contents of the second cloned Template. Anka CLI will intelligently know that the layers are still in use by the new Template.

Here is a diagram of a common and recommended pattern for creating Templates/Tags:

11.1.0 (stopped)  | 
                  | -> clone -> xcode12.3 (stopped) |
                  |                                 | -> clone -> project1 (with fastlane-v1.X) (suspended)
                  |                                 | -> clone -> project2 (with fastlane-v2.X) (suspended)
                  |
                  | -> clone -> xcode11.7 (stopped) -> clone -> project3 (suspended)

Note the “stopped” state of the first two cloned Templates. Unless you plan on using the vanilla 11.1.0 or xcode Templates, the suspended state is a waste of space. However, you do typically want to suspend the Templates/Tags that your CI/CD and developers will use.

You can configure and prepare Xcode without a GUI using the following commands:

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer
sudo xcodebuild -license accept
sudo xcodebuild -runFirstLaunch
sudo DevToolsSecurity -enable

You can also create multiple tags on top of a single Template. This is done by simply starting the VM, stopping/suspending once changes are made, and then pushing to the registry with a new Tag. However, this causes problems when trying to quickly switch between tags for different projects, as the Anka Build Cloud only allows a single Tag on a machine at once. This means that switching would require cause a download to happen, and depending on the size of the other tag, could slow down your CI/CD considerably. This is where cloned Templates shine. Multiple Templates for multiple projects can exist at once on a host, all sharing underlying layers and cutting down on disk space usage and time to start VMs for your CI/CD jobs.

If you’re interested in Infrastructure as Code to automate the creation of your Templates and Tags, you have several options:

1. Write scripts that:
   • Sequentially parse and execute commands from a data serialization language like JSON or YAML inside of the VM.
   • Or execute commands inside of the VM from within the script itself (example).
2. Use the Packer Builder: https://github.com/veertuinc/packer-builder-veertu-anka