* loop sends an initial query to detect infinite forwarding
loops in configured upstream DNS servers and fast exit with
an error (its a fatal misconfiguration on the network that
will otherwise cause resolvers to consume memory/CPU until
crashing, masking the problem)
* https://github.com/coredns/coredns/tree/master/plugin/loop
* loadbalance randomizes the ordering of A, AAAA, and MX records
in responses to provide round-robin load balancing (as usual,
clients may still cache responses though)
* https://github.com/coredns/coredns/tree/master/plugin/loadbalance
* Prefer InternalIP and ExternalIP over the node's hostname,
to match upstream behavior and kubeadm
* Previously, hostname-override was used to set node names
to internal IP's to work around some cloud providers not
resolving hostnames for instances (e.g. DO droplets)
* Updating the `terraform-provider-ct` plugin is known to produce
a `user_data` diff in all pre-existing clusters. Applying the
diff to pre-existing cluster destroys controller nodes
* Ignore changes to controller `user_data`. Once all managed
clusters use a release containing this change, it is possible
to update the `terraform-provider-ct` plugin (worker `user_data`
will still be modified)
* Changing the module `ref` for an existing cluster and
re-applying is still NOT supported (although this PR
would protect controllers from being destroyed)
* Improve the workers "round-robin" DNS FQDN that is created
with each cluster by adding AAAA records
* CNAME's resolving to the DigitalOcean `workers_dns` output
can be followed to find a droplet's IPv4 or IPv6 address
* The CNI portmap plugin doesn't support IPv6. Hosting IPv6
apps is possible, but requires editing the nginx-ingress
addon with `hostNetwork: true`
* Run at least two replicas of CoreDNS to better support
rolling updates (previously, kube-dns had a pod nanny)
* On multi-master clusters, set the CoreDNS replica count
to match the number of masters (e.g. a 3-master cluster
previously used replicas:1, now replicas:3)
* Add AntiAffinity preferred rule to favor distributing
CoreDNS pods across controller nodes nodes
* Continue to ensure scheduler and controller-manager run
at least two replicas to support performing kubectl edits
on single-master clusters (no change)
* For multi-master clusters, set scheduler / controller-manager
replica count to the number of masters (e.g. a 3-master cluster
previously used replicas:2, now replicas:3)
* Require a terraform-provider-digitalocean plugin version of
1.0 or higher within the same major version (e.g. allow 1.1 but
not 2.0)
* Change requirement from ~> 0.1.2 (which allowed up to but not
including 1.0 release)
* Add new bird and felix readiness checks
* Read MTU from ConfigMap veth_mtu
* Add RBAC read for serviceaccounts
* Remove invalid description from CRDs
* Release v1.11.1 erroneously left Fedora Atomic clusters using
the v1.11.0 Kubelet. The rest of the control plane ran v1.11.1
as expected
* Update Kubelet from v1.11.0 to v1.11.1 so Fedora Atomic matches
Container Linux
* Container Linux modules were not affected
* Adjust firewall rules, security groups, cloud load balancers,
and generated kubeconfig's
* Facilitates some future simplifications and cost reductions
* Bare-Metal users who exposed kube-apiserver on a WAN via their
router or load balancer will need to adjust its configuration.
This is uncommon, most apiserver are on LAN and/or behind VPN
so no routing infrastructure is configured with the port number
* Raise minimum Terraform version to v0.11.0
* Terraform v0.11.x has been supported since Typhoon v1.9.2
and Terraform v0.10.x was last released in Nov 2017. I'd like
to stop worrying about v0.10.x and remove migration docs as
a later followup
* Migration docs docs/topics/maintenance.md#terraform-v011x
* (containerized) kube-proxy warns that it is unable to
load the ip_vs kernel module despite having the correct
mounts. Atomic uses an xz compressed module and modprobe
in the container was not compiled with compression support
* Workaround issue for now by always loading ip_vs on-host
* https://github.com/kubernetes/kubernetes/issues/60
* Use the upstream bootkube image packaged with the
required metadata to be usable as a system container
under systemd
* Run bootkube with runc so no host level components
use Docker any more. Docker is still the runtime
* Remove bootkube script and old systemd unit
* Change kubelet system image to use --cgroups-per-qos=true
(default) instead of false
* Change kubelet system image to use --enforce-node-allocatable=pods
instead of an empty string
* Fix kubelet port-forward on Google Cloud / Fedora Atomic
* Mount the host's /etc/hosts in kubelet system containers
* Problem: kubelet runc system containers on Atomic were not
mounting the host's /etc/hosts, like rkt-fly does on Container
Linux. `kubectl port-forward` calls socat with localhost. DNS
servers on AWS, DO, and in many bare-metal environments resolve
localhost to the caller as a convenience. Google Cloud notably
does not nor is it required to do so and this surfaced the
missing /etc/hosts in runc kubelet namespaces.
* Enable etcd v3.3 metrics to expose metrics for
scraping by Prometheus
* Use k8s.gcr.io instead of gcr.io/google_containers
* Add flexvolume plugin mount to controller manager
* Update kube-dns from v1.14.8 to v1.14.9
* Mount /opt/cni/bin in kubelet system container so
CNI plugin binaries can be found. Before, flannel
worked because the kubelet falls back to flannel
plugin baked into the hyperkube (undesired)
* Move the CNI bin install location later, since /opt
changes may be lost between ostree rebases
* Use the upstream hyperkube image packaged with the
required metadata to be usable as a system container
under systemd
* Fix port-forward since socat is included
* Update manifests for Kubernetes v1.10.0
* Update etcd from v3.3.2 to v3.3.3
* Add disk_type optional variable on AWS
* Remove redundant kubeconfig copy on AWS
* Distribute etcd secres only to controllers
* Organize module variables and ssh steps
* Use etcd v3.3 --listen-metrics-urls to expose only metrics
data via http://0.0.0.0:2381 on controllers
* Add Prometheus discovery for etcd peers on controller nodes
* Temporarily drop two noisy Prometheus alerts
* AWS and Google Cloud make use of auto-scaling groups
and managed instance groups, respectively. As such, the
kubeconfig is already held in cloud user-data
* Controller instances are provisioned with a kubeconfig
from user-data. Its redundant to use a Terraform remote
file copy step for the kubeconfig.
* Calico isn't viable on Digital Ocean because their firewalls
do not support IP-IP protocol. Its not viable to run a cluster
without firewalls just to use Calico.
* Remove the caveat note. Don't allow users to shoot themselves
in the foot
* Introduce the ability to support Container Linux Config
"snippets" for controllers and workers on cloud platforms.
This allows end-users to customize hosts by providing Container
Linux configs that are additively merged into the base configs
defined by Typhoon. Config snippets are validated, merged, and
show any errors during `terraform plan`
* Example uses include adding systemd units, network configs,
mounts, files, raid arrays, or other disk provisioning features
provided by Container Linux Configs (using Ignition low-level)
* Requires terraform-provider-ct v0.2.1 plugin
* Add a node-role.kubernetes.io/controller="true" node label
to controllers so Prometheus service discovery can filter to
services that only run on controllers (i.e. masters)
* Leave node-role.kubernetes.io/master="" untouched as its
a Kubernetes convention
* Set Kubelet search path for flexvolume plugins
to /var/lib/kubelet/volumeplugins
* Add support for flexvolume plugins on AWS, GCE, and DO
* See 9548572d98 which added flexvolume support for bare-metal
* Remove PersistentVolumeLabel admission controller flag
* Switch Deployments and DaemonSets to apps/v1
* Minor update to pod-checkpointer image version
* Add flannel service account and limited RBAC cluster role
* Change DaemonSets to tolerate NoSchedule and NoExecute taints
* Remove deprecated apiserver --etcd-quorum-read flag
* Update Calico from v3.0.1 to v3.0.2
* Add Calico GlobalNetworkSet CRD
* https://github.com/poseidon/terraform-render-bootkube/pull/44
* Change port range from keyword "all" to "1-65535", which is the
same but with digitalocean provider 0.1.3 doesn't produce a diff
* Rearrange egress firewall rules to order the Digtial Ocean API
and provider returns. In current testing, this fixes the last diff
that was present on `terraform plan`.
* Allow kube-dns to respond to DNS queries with a custom
suffix, instead of the default 'cluster.local'
* Useful when multiple clusters exist on the same local
network and wish to query services on one another
* When restarting masters, `etcd-member.service` may fail to lookup peers if
/etc/resolv.conf hasn't been populated yet. Require the wait-for-dns.service.
* Update hyperkube from v1.8.3 to v1.8.4
* Remove flock from bootstrap-apiserver and kube-apiserver
* Remove unused critical-pod annotations in manifests
* Use service accounts for kube-proxy and pod-checkpointer
* Update Calico from v2.6.1 to v2.6.3
* Update flannel from v0.9.0 to v0.9.1
* Remove Calico termination grace period to prevent calico
from getting stuck for extended periods
* https://github.com/poseidon/terraform-render-bootkube/pull/29
* Change controllers ASG to heterogeneous EC2 instances
* Create DNS records for each controller's private IP for etcd
* Change etcd to run on-host, across controllers (etcd-member.service)
* Reduce time to bootstrap a cluster
* Deprecate self-hosted-etcd on the AWS platform
* Change controllers from a managed group to individual instances
* Create discrete DNS records to each controller's private IP for etcd
* Change etcd to run on-host, across controllers (etcd-member.service)
* Reduce time to bootstrap a cluster
* Deprecate self-hosted-etcd on the Google Cloud platform
* Kubernetes v1.8.2 fixes a memory leak in the v1.8.1 apiserver
* Switch to using the `gcr.io/google_containers/hyperkube` for the
on-host kubelet and shutdown drains
* Update terraform-render-bootkube manifests generation
* Update flannel from v0.8.0 to v0.9.0
* Add `hairpinMode` to flannel CNI config
* Add `--no-negcache` to kube-dns dnsmasq
* Run etcd peers with TLS across controller nodes
* Deprecate self-hosted-etcd on the Digital Ocean platform
* Distribute etcd TLS certificates as part of initial provisioning
* Check the status of etcd by running `systemctl status etcd-member`
* Mounting NFS exports as volumes from some NFS servers fails because
the kubelet isn't starting rpc-statd as expected. Describing pods
that are stuck creating shows rpc.statd is required for remote locking
* Starting rpc-statd.service resolves the issue and all NFS mounts
seem to be working.
* Recommended approach https://github.com/coreos/bugs/issues/2074
* Mount host /opt/cni/bin in Kubelet to use host's CNI plugins
* Switch /var/run/kubelet-pod.uuid to /var/cache/kubelet-pod.uuid
to persist between reboots and cleanup old Kubelet pods
* Organize Kubelet flags in alphabetical order
* Calico on GCE with IP-in-IP encapsulation and MTU 1440
* Calico on DO with IP-in-IP encapsulation and MTU 1440
* Digital Ocean firewalls don't support IPIP protocol yet
* Without a reference a Digital Ocean tag object, terraform may
try to create a firewall rule before a tag actually exists. By
referencing the actual tag objects, the dependency order is
implied
Dalton Hubble
Tamer Fahmy
Ben Drucker
William Zhang
Sean Swehla
irontoby
Barak Michener
Lars Fenneberg
Vincent Palmer