* When a worker managed instance group's (MIG) instance template
changes (including machine type, disk size, or Butane snippets
but excluding new AMIs), use Google Cloud's rolling update features
to ensure instances match declared state
* Ignore new AMIs since Fedora CoreOS and Flatcar Linux nodes
already auto-update and reboot themselves
* Rolling updates will create surge instances, wait for health
checks, then delete old instances (0 unavilable instances)
* Instances are replaced to ensure new Ignition/Butane snippets
are respected
* Add managed instance group autohealing (i.e. health checks) to
ensure new instances' Kubelet is running
Renames
* Name apiserver and kubelet health checks consistently
* Rename MIG from `${var.name}-worker-group` to `${var.name}-worker`
Rel: https://cloud.google.com/compute/docs/instance-groups/rolling-out-updates-to-managed-instance-groups
* Requires poseidon v0.11+ and Flatcar Linux 3185.0.0+ (action required)
* Previously, Flatcar Linux configs have been parsed as Container
Linux Configs to Ignition v2.2.0 specs by poseidon/ct
* Flatcar Linux starting in 3185.0.0 now supports Ignition v3.x specs
(which are rendered from Butane Configs, like Fedora CoreOS)
* poseidon/ct v0.11.0 adds support for the flatcar Butane Config
variant so that Flatcar Linux can use Ignition v3.x
Rel:
* [Flatcar Support](https://flatcar-linux.org/docs/latest/provisioning/ignition/specification/#ignition-v3)
* [poseidon/ct support](https://github.com/poseidon/terraform-provider-ct/pull/131)
* Use the official Kinvolk Flatcar Linux image on Google Cloud
* Change `os_image` from a custom image name to `flatcar-stable`
(default), `flatcar-beta`, or `flatcar-alpha` (**action required**)
* Change `os_image` from a required to an optional variable
* Promote Typhoon on Flatcar Linux / Google Cloud to stable
* Remove docs about needing to upload a Flatcar Linux image
manually on Google Cloud and drop support for custom images
* Both Flatcar Linux and Fedora CoreOS use systemd-resolved,
but they setup /etc/resolv.conf symlinks differently
* Prefer using /run/systemd/resolve/resolv.conf directly, which
also updates to reflect runtime changes (e.g. resolvectl)
* Update `null` provider to allow use of v3.1.x releases,
instead of being stuck on v2.1.2
* Update min versions in terraform-render-boostrap
https://github.com/poseidon/terraform-render-bootstrap/pull/287
* Document the recommended versions of Terraform cloud providers
* Remove `/sys/fs/cgroup/systemd` mount since Flatcar Linux
uses cgroups v2
* Flatcar Linux's `docker` switched from the `cgroupfs` to
`systemd` driver without notice
* Add `node_taints` variable to worker modules to set custom
initial node taints on cloud platforms that support auto-scaling
worker pools of heterogeneous nodes (i.e. AWS, Azure, GCP)
* Worker pools could use custom `node_labels` to allowed workloads
to select among differentiated nodes, while custom `node_taints`
allows a worker pool's nodes to be tainted as special to prevent
scheduling, except by workloads that explicitly tolerate the
taint
* Expose `daemonset_tolerations` in AWS, Azure, and GCP kubernetes
cluster modules, to determine whether `kube-system` components
should tolerate the custom taint (advanced use covered in docs)
Rel: #550, #663Closes#429
* Allow terraform-provider-ct versions v0.6+ (e.g. v0.7.1)
Before, only v0.6.x point updates were allowed
* Update terraform-provider-ct to v0.7.1 in docs
* READ the docs before updating terraform-provider-ct,
as changing worker user-data is handled differently
by different cloud platforms
