* Define a dual-stack virtual network with both IPv4 and IPv6 private
address space. Change `host_cidr` variable (string) to a `network_cidr`
variable (object) with "ipv4" and "ipv6" fields that list CIDR strings.
* Define dual-stack controller and worker subnets. Disable Azure
default outbound access (a deprecated fallback mechanism)
* Enable dual-stack load balancing to Kubernetes Ingress by adding
a public IPv6 frontend IP and LB rule to the load balancer.
* Enable worker outbound IPv6 connectivity through load balancer
SNAT by adding an IPv6 frontend IP and outbound rule
* Configure controller nodes with a public IPv6 address to provide
direct outbound IPv6 connectivity
* Add an IPv6 worker backend pool. Azure requires separate IPv4 and
IPv6 backend pools, though the health probe can be shared
* Extend network security group rules for IPv6 source/destinations
Checklist:
Access to controller and worker nodes via IPv6 addresses:
* SSH access to controller nodes via public IPv6 address
* SSH access to worker nodes via (private) IPv6 address (via
controller)
Outbound IPv6 connectivity from controller and worker nodes:
```
nc -6 -zv ipv6.google.com 80
Ncat: Version 7.94 ( https://nmap.org/ncat )
Ncat: Connected to [2607:f8b0:4001:c16::66]:80.
Ncat: 0 bytes sent, 0 bytes received in 0.02 seconds.
```
Serve Ingress traffic via IPv4 or IPv6 just requires setting
up A and AAAA records and running the ingress controller with
`hostNetwork: true` since, hostPort only forwards IPv4 traffic
* Output the network security group name and address prefixes
for controller nodes, to allow adding custom network security
rules that apply specifically to controller nodes
* Typhoon now consistently uses Butane Configs for snippets
(variant `fcos` or `flatcar`). Previously snippets were either
Butane Configs (on FCOS) or Container Linux Configs (on Flatcar)
* Update docs on uploading Flatcar Linux DigitalOcean images
* Update docs on uploading Fedora CoreOS Azure images
* Change subnet references to source and destinations prefixes
(plural)
* Remove references to a resource group in some load balancing
components, which no longer require it (inferred)
* Rename `worker_address_prefix` output to `worker_address_prefixes`
* NLB subnets assigned both IPv4 and IPv6 addresses
* NLB DNS name has both A and AAAA records
* NLB to target node traffic is IPv4 (no change),
no change to security groups needed
* Ingresses exposed through the recommended Nginx
Ingress Controller addon will be accessible via
IPv4 or IPv6. No change is needed to the app's
CNAME to NLB record
Related: https://aws.amazon.com/about-aws/whats-new/2020/11/network-load-balancer-supports-ipv6/
* CoreOS Container Linux was deprecated in v1.18.3
* Continue transitioning docs and modules from supporting
both CoreOS and Flatcar "variants" of Container Linux to
now supporting Flatcar Linux and equivalents
Action Required: Update the Flatcar Linux modules `source`
to replace `s/container-linux/flatcar-linux`. See docs for
examples
* Use docker to run the `kubelet.service` container
* Update Kubelet mounts to match Fedora CoreOS
* Remove unused `/etc/ssl/certs` mount (see
https://github.com/poseidon/typhoon/pull/810)
* Remove unused `/usr/share/ca-certificates` mount
* Remove `/etc/resolv.conf` mount, Docker default is ok
* Change `delete-node.service` to use docker instead of rkt
and inline ExecStart, as was done on Fedora CoreOS
* Fix permission denied on shutdown `delete-node`, caused
by the kubeconfig mount changing with the introduction of
node TLS bootstrap
Background
* podmand, rkt, and runc daemonless container process runners
provide advantages over the docker daemon for system containers.
Docker requires workarounds for use in systemd units where the
ExecStart must tail logs so systemd can monitor the daemonized
container. https://github.com/moby/moby/issues/6791
* Why switch then? On Flatcar Linux, podman isn't shipped. rkt
works, but isn't developing while container standards continue
to move forward. Typhoon has used runc for the Kubelet runner
before in Fedora Atomic, but its more low-level. So we're left
with Docker, which is less than ideal, but shipped in Flatcar
* Flatcar Linux appears to be shifting system components to
use docker, which does provide some limited guards against
breakages (e.g. Flatcar cannot enable docker live restore)
* DigitalOcean introduced Virtual Private Cloud (VPC) support
to match other clouds and enhance the prior "private networking"
feature. Before, droplet's belonging to different clusters (but
residing in the same region) could reach one another (although
Typhoon firewall rules prohibit this). Now, droplets in a VPC
reside in their own network
* https://www.digitalocean.com/docs/networking/vpc/
* Create droplet instances in a VPC per cluster. This matches the
design of Typhoon AWS, Azure, and GCP.
* Require `terraform-provider-digitalocean` v1.16.0+ (action required)
* Output `vpc_id` for use with an attached DigitalOcean
loadbalancer
* Promote DigitalOcean from alpha to beta for Fedora
CoreOS and Flatcar Linux
* Upgrade mkdocs-material and PyPI packages for docs
* Replace docs mentions of Container Linux with Flatcar
Linux and move docs/cl to docs/flatcar-linux
* Deprecate CoreOS Container Linux support. Its still
usable for some time, but start removing docs
* Kubernetes plans to stop releasing the hyperkube container image
* Upstream will continue to publish `kube-apiserver`, `kube-controller-manager`,
`kube-scheduler`, and `kube-proxy` container images to `k8s.gcr.io`
* Upstream will publish Kubelet only as a binary for distros to package,
either as a DEB/RPM on traditional distros or a container image on
container-optimized operating systems
* Typhoon will package the upstream Kubelet (checksummed) and its
dependencies as a container image for use on CoreOS Container Linux,
Flatcar Linux, and Fedora CoreOS
* Update the Typhoon container image security policy to list
`quay.io/poseidon/kubelet`as an official distributed artifact
Hyperkube: https://github.com/kubernetes/kubernetes/pull/88676
Kubelet Container Image: https://github.com/poseidon/kubelet
Kubelet Quay Repo: https://quay.io/repository/poseidon/kubelet
* Allow users to extend the route table using a data reference
and adding route resources (e.g. unusual peering setups)
* Note: Internally connecting AWS clusters can reduce cross-cloud
flexibility and inhibits blue-green cluster patterns. It is not
recommended
* Original tutorials favored including the platform (e.g.
google-cloud) in modules (e.g. google-cloud-yavin). Prefer
naming conventions where each module / cluster has a simple
name (e.g. yavin) since the platform is usually redundant
* Retain the example cluster naming themes per platform
* Describe kube-apiserver load balancing on each platform
* Describe HTTP/S Ingress load balancing on each platform
* Describe TCP/UDP load balancing apps on each platform
(some clouds don't support UDP)
* Describe firewall customization (e.g. for TCP/UDP apps)
* Update IPv6 status for each platform
* For Container Linux or Flatcar Linux alpha/beta/stable,
continue using the `cgroupfs` driver
* For Fedora Atomic, continue using the `systemd` driver
* For Flatcar Linux Edge, use the `systemd` driver
* Switch tutorials from using ~/.terraformrc to using the 3rd-party
plugin directory so 3rd-party plugins can be pinned
* Continue to show using terraform-provider-ct v0.2.2. Updating to
a newer version is only safe once all managed clusters are v1.12.2
or higher
* Allowing serving IPv6 applications via Kubernetes Ingress
on Typhoon Google Cloud clusters
* Add `ingress_static_ipv6` output variable for use in AAAA
DNS records
* Typhoon for Fedora Atomic uses system containers, container
images containing metadata, but built directly from upstream
and published and serve through Quay.io
* https://github.com/poseidon/system-containers
