Migrate Fedora CoreOS AWS to a static pod control plane

* Run a kube-apiserver, kube-scheduler, and kube-controller-manager
static pod on each controller node. Previously, kube-apiserver was
self-hosted as a DaemonSet across controllers and kube-scheduler
and kube-controller-manager were a Deployment (with 2 or
controller_count many replicas).
* Remove bootkube bootstrap and pivot to self-hosted
* Remove pod-checkpointer manifests (no longer needed)
This commit is contained in:
Dalton Hubble 2019-09-02 21:10:30 -07:00
parent 4a7083d94a
commit b60a2ecdf7
7 changed files with 87 additions and 49 deletions

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@ -11,7 +11,7 @@ Typhoon distributes upstream Kubernetes, architectural conventions, and cluster
## Features <a href="https://www.cncf.io/certification/software-conformance/"><img align="right" src="https://storage.googleapis.com/poseidon/certified-kubernetes.png"></a>
* Kubernetes v1.15.3 (upstream, via [kubernetes-incubator/bootkube](https://github.com/kubernetes-incubator/bootkube))
* Kubernetes v1.15.3 (upstream)
* Single or multi-master, [Calico](https://www.projectcalico.org/) or [flannel](https://github.com/coreos/flannel) networking
* On-cluster etcd with TLS, [RBAC](https://kubernetes.io/docs/admin/authorization/rbac/)-enabled, [network policy](https://kubernetes.io/docs/concepts/services-networking/network-policies/)
* Advanced features like [worker pools](https://typhoon.psdn.io/advanced/worker-pools/), [spot](https://typhoon.psdn.io/cl/aws/#spot) workers, and [snippets](https://typhoon.psdn.io/advanced/customization/#container-linux) customization

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@ -1,6 +1,6 @@
# Self-hosted Kubernetes assets (kubeconfig, manifests)
module "bootkube" {
source = "git::https://github.com/poseidon/terraform-render-bootkube.git?ref=98cc19f80f2c4c3ddc63fc7aea6320e74bec561a"
source = "git::https://github.com/poseidon/terraform-render-bootkube.git?ref=6e59af71138bc5f784453873074de16e7ee150eb"
cluster_name = var.cluster_name
api_servers = [format("%s.%s", var.cluster_name, var.dns_zone)]

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@ -107,33 +107,48 @@ systemd:
RestartSec=10
[Install]
WantedBy=multi-user.target
- name: bootkube.service
- name: bootstrap.service
contents: |
[Unit]
Description=Bootstrap a Kubernetes control plane
ConditionPathExists=!/opt/bootkube/init_bootkube.done
Description=Bootstrap Kubernetes control plane
ConditionPathExists=!/opt/bootstrap/bootstrap.done
[Service]
Type=oneshot
RemainAfterExit=true
WorkingDirectory=/opt/bootkube
ExecStart=/usr/bin/bash -c 'set -x && \
[ -n "$(ls /opt/bootkube/assets/manifests-*/* 2>/dev/null)" ] && mv /opt/bootkube/assets/manifests-*/* /opt/bootkube/assets/manifests && rm -rf /opt/bootkube/assets/manifests-* && exec podman run --name bootkube --privileged \
WorkingDirectory=/opt/bootstrap
ExecStartPre=-/usr/bin/bash -c 'set -x && [ -n "$(ls /opt/bootstrap/assets/manifests-*/* 2>/dev/null)" ] && mv /opt/bootstrap/assets/manifests-*/* /opt/bootstrap/assets/manifests && rm -rf /opt/bootstrap/assets/manifests-*'
ExecStart=/usr/bin/podman run --name bootstrap \
--network host \
--volume /opt/bootkube/assets:/assets \
--volume /etc/kubernetes:/etc/kubernetes \
quay.io/coreos/bootkube:v0.14.0 \
/bootkube start --asset-dir=/assets'
ExecStartPost=/bin/touch /opt/bootkube/init_bootkube.done
--volume /opt/bootstrap/assets:/assets:ro,Z \
--volume /opt/bootstrap/apply:/apply:ro,Z \
k8s.gcr.io/hyperkube:v1.15.3 \
/apply
ExecStartPost=/bin/touch /opt/bootstrap/bootstrap.done
ExecStartPost=-/usr/bin/podman stop bootstrap
storage:
directories:
- path: /etc/kubernetes
- path: /opt/bootkube
- path: /opt/bootstrap
files:
- path: /etc/kubernetes/kubeconfig
mode: 0644
contents:
inline: |
${kubeconfig}
- path: /opt/bootstrap/apply
mode: 0544
contents:
inline: |
#!/bin/bash -e
export KUBECONFIG=/assets/auth/kubeconfig
until kubectl version; do
echo "Waiting for static pod control plane"
sleep 5
done
until kubectl apply -f /assets/manifests -R; do
echo "Retry applying manifests"
sleep 5
done
- path: /etc/sysctl.d/reverse-path-filter.conf
contents:
inline: |

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@ -44,6 +44,28 @@ resource "aws_security_group_rule" "controller-etcd-metrics" {
source_security_group_id = aws_security_group.worker.id
}
# Allow Prometheus to scrape kube-scheduler
resource "aws_security_group_rule" "controller-scheduler-metrics" {
security_group_id = aws_security_group.controller.id
type = "ingress"
protocol = "tcp"
from_port = 10251
to_port = 10251
source_security_group_id = aws_security_group.worker.id
}
# Allow Prometheus to scrape kube-controller-manager
resource "aws_security_group_rule" "controller-manager-metrics" {
security_group_id = aws_security_group.controller.id
type = "ingress"
protocol = "tcp"
from_port = 10252
to_port = 10252
source_security_group_id = aws_security_group.worker.id
}
resource "aws_security_group_rule" "controller-vxlan" {
count = var.networking == "flannel" ? 1 : 0

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@ -1,7 +1,11 @@
# Secure copy etcd TLS assets to controllers.
# Secure copy assets to controllers.
resource "null_resource" "copy-controller-secrets" {
count = var.controller_count
depends_on = [
module.bootkube,
]
connection {
type = "ssh"
host = aws_instance.controllers.*.public_ip[count.index]
@ -44,6 +48,11 @@ resource "null_resource" "copy-controller-secrets" {
destination = "$HOME/etcd-peer.key"
}
provisioner "file" {
source = var.asset_dir
destination = "$HOME/assets"
}
provisioner "remote-exec" {
inline = [
"sudo mkdir -p /etc/ssl/etcd/etcd",
@ -56,18 +65,21 @@ resource "null_resource" "copy-controller-secrets" {
"sudo mv etcd-peer.key /etc/ssl/etcd/etcd/peer.key",
"sudo chown -R etcd:etcd /etc/ssl/etcd",
"sudo chmod -R 500 /etc/ssl/etcd",
"sudo mv $HOME/assets /opt/bootstrap/assets",
"sudo mkdir -p /etc/kubernetes/bootstrap-secrets",
"sudo cp -r /opt/bootstrap/assets/tls/* /etc/kubernetes/bootstrap-secrets/",
"sudo cp /opt/bootstrap/assets/auth/kubeconfig /etc/kubernetes/bootstrap-secrets/",
"sudo cp -r /opt/bootstrap/assets/static-manifests/* /etc/kubernetes/manifests/"
]
}
}
# Secure copy bootkube assets to ONE controller and start bootkube to perform
# one-time self-hosted cluster bootstrapping.
resource "null_resource" "bootkube-start" {
# Connect to a controller to perform one-time cluster bootstrap.
resource "null_resource" "bootstrap" {
depends_on = [
module.bootkube,
null_resource.copy-controller-secrets,
module.workers,
aws_route53_record.apiserver,
null_resource.copy-controller-secrets,
]
connection {
@ -77,15 +89,9 @@ resource "null_resource" "bootkube-start" {
timeout = "15m"
}
provisioner "file" {
source = var.asset_dir
destination = "$HOME/assets"
}
provisioner "remote-exec" {
inline = [
"sudo mv $HOME/assets /opt/bootkube",
"sudo systemctl start bootkube",
"sudo systemctl start bootstrap",
]
}
}

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@ -78,7 +78,6 @@ systemd:
storage:
directories:
- path: /etc/kubernetes
- path: /opt/bootkube
files:
- path: /etc/kubernetes/kubeconfig
mode: 0644

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@ -7,7 +7,7 @@ In this tutorial, we'll create a Kubernetes v1.15.3 cluster on AWS with Fedora C
We'll declare a Kubernetes cluster using the Typhoon Terraform module. Then apply the changes to create a VPC, gateway, subnets, security groups, controller instances, worker auto-scaling group, network load balancer, and TLS assets.
Controllers are provisioned to run an `etcd-member` peer and a `kubelet` service. Workers run just a `kubelet` service. A one-time [bootkube](https://github.com/kubernetes-incubator/bootkube) bootstrap schedules the `apiserver`, `scheduler`, `controller-manager`, and `coredns` on controllers and schedules `kube-proxy` and `calico` (or `flannel`) on every node. A generated `kubeconfig` provides `kubectl` access to the cluster.
Controllers hosts are provisioned to run an `etcd-member` peer and a `kubelet` service. Worker hosts run a `kubelet` service. Controller nodes run `kube-apiserver`, `kube-scheduler`, `kube-controller-manager`, and `coredns`, while `kube-proxy` and `calico` (or `flannel`) run on every node. A generated `kubeconfig` provides `kubectl` access to the cluster.
## Requirements
@ -94,7 +94,7 @@ Reference the [variables docs](#variables) or the [variables.tf](https://github.
## ssh-agent
Initial bootstrapping requires `bootkube.service` be started on one controller node. Terraform uses `ssh-agent` to automate this step. Add your SSH private key to `ssh-agent`.
Initial bootstrapping requires `bootstrap.service` be started on one controller node. Terraform uses `ssh-agent` to automate this step. Add your SSH private key to `ssh-agent`.
```sh
ssh-add ~/.ssh/id_rsa
@ -121,9 +121,9 @@ Apply the changes to create the cluster.
```sh
$ terraform apply
...
module.aws-tempest.null_resource.bootkube-start: Still creating... (4m50s elapsed)
module.aws-tempest.null_resource.bootkube-start: Still creating... (5m0s elapsed)
module.aws-tempest.null_resource.bootkube-start: Creation complete after 11m8s (ID: 3961816482286168143)
module.aws-tempest.null_resource.bootstrap: Still creating... (4m50s elapsed)
module.aws-tempest.null_resource.bootstrap: Still creating... (5m0s elapsed)
module.aws-tempest.null_resource.bootstrap: Creation complete after 5m8s (ID: 3961816482286168143)
Apply complete! Resources: 98 added, 0 changed, 0 destroyed.
```
@ -147,22 +147,18 @@ List the pods.
```
$ kubectl get pods --all-namespaces
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system calico-node-1m5bf 2/2 Running 0 34m
kube-system calico-node-7jmr1 2/2 Running 0 34m
kube-system calico-node-bknc8 2/2 Running 0 34m
kube-system coredns-1187388186-wx1lg 1/1 Running 0 34m
kube-system coredns-1187388186-qjnvp 1/1 Running 0 34m
kube-system kube-apiserver-4mjbk 1/1 Running 0 34m
kube-system kube-controller-manager-3597210155-j2jbt 1/1 Running 1 34m
kube-system kube-controller-manager-3597210155-j7g7x 1/1 Running 0 34m
kube-system kube-proxy-14wxv 1/1 Running 0 34m
kube-system kube-proxy-9vxh2 1/1 Running 0 34m
kube-system kube-proxy-sbbsh 1/1 Running 0 34m
kube-system kube-scheduler-3359497473-5plhf 1/1 Running 0 34m
kube-system kube-scheduler-3359497473-r7zg7 1/1 Running 1 34m
kube-system pod-checkpointer-4kxtl 1/1 Running 0 34m
kube-system pod-checkpointer-4kxtl-ip-10-0-3-155 1/1 Running 0 33m
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-system calico-node-1m5bf 2/2 Running 0 34m
kube-system calico-node-7jmr1 2/2 Running 0 34m
kube-system calico-node-bknc8 2/2 Running 0 34m
kube-system coredns-1187388186-wx1lg 1/1 Running 0 34m
kube-system coredns-1187388186-qjnvp 1/1 Running 0 34m
kube-system kube-apiserver-4mjbk 1/1 Running 0 34m
kube-system kube-controller-manager-ip-10-0-3-155 1/1 Running 0 34m
kube-system kube-proxy-14wxv 1/1 Running 0 34m
kube-system kube-proxy-9vxh2 1/1 Running 0 34m
kube-system kube-proxy-sbbsh 1/1 Running 0 34m
kube-system kube-scheduler-ip-10-0-3-155 1/1 Running 1 34m
```
## Going Further