Differences between revisions 14 and 23 (spanning 9 versions)

persica cluster

This is a cluster of three identical nodes, named persica1/2/3

Alma Linux 9.1 x64
Dell Optiplex 9020 Micro
- Intel Core i5-4590T @ 2.00 GHz
- 16gb DDR3-1600
- 128gb SSD

I last touched this in April 2023 and it was very annoying to get as far as I did. Next time I look at it, I think I will rebuild the cluster from scratch again, and use a different guide. Something with actual explanations and a few opinions, like this one: https://github.com/hobby-kube/guide

Contents

persica cluster

Another rebuild attempt in late 2023

A few changes for this one:

I'm going to use Rancher this time, or that guide linked above
Alma 9.2 because it's the latest
Move them to the "subnet" of 192.168.1.32/29 so I can configure the router to give them DHCP options easily
- persica1 / 192.168.1.33
- persica2 / 192.168.1.34
- persica3 / 192.168.1.35
Put the controller node onto asval rather than illustrious, which in this case might be the rancher docker container
- asval / 192.168.1.32 (should probably be a static IP)
- persica / CNAME to asval
Go with Longhorn for PVCs
Dunno what to do about ingress yet

Prepare asval controller node

OS imaging

Using the Raspberry Pi Imager app, start with RPi OS Lite 64-bit, suitable for the RPi 3B+

It lets you make some customisations before flashing, which is really nice:

Set hostname to asval
Enable SSH
- Password auth (I would use SSH but it didn't work right for me and I couldn't sudo later)
Set username and password
- pi // <something new>
No WLAN
Set locale to Australia/Sydney, us keyboard
Disable telemetry

Config

Login as pi@asval and copy your SSH key there
Install base packages
```
apt install -y vim git screen ack
```
Enable I2C bus for the RTC
- Run raspi-config
  - Interface Options -> I2C -> Enable
- dtparam=i2c_arm=on has already been enabled in /boot/config.txt for us
- i2c_dev module should now/already be loaded so we're ready to go I hope
- Reboot now, it can't hurt
Install i2c tools
```
apt install -y i2c-tools
```
Detect the device on i2c bus: i2cdetect -y 1
- Should appear at 0x68
Enable the kernel driver for it, or something, by adding a devicetree overlay. Append this to the end of /boot/config.txt
```
dtoverlay=i2c-rtc,ds3231
```
Reboot again to load the device tree overlay that we just configured
Again detect the device on i2c bus: i2cdetect -y 1
- Should appear at 0x68, BUT with "UU" at the address this time

Remove the fake hardware clock

systemctl disable fake-hwclock --now
apt purge -y fake-hwclock

In theory everything just works now thanks to a udev rule: https://www.raspberrypi.org/forums/viewtopic.php?t=209700

root@asval:~# cat /lib/udev/rules.d/85-hwclock.rules
# Set the System Time from the Hardware Clock and set the kernel's timezone
# value to the local timezone when the kernel clock module is loaded.
KERNEL=="rtc0", RUN+="/usr/lib/udev/hwclock-set $root/$name"

Install chrony so it manages the hardware clock
```
apt install -y chrony
```
It'll do the rest once it's installed and synced. Try some commands to see how it's fairing:
```
chronyc sources
chronyc tracking
```

Disable unneeded stuff

I'm using asval as a network appliance, so I don't need the wifi and bluetooth radios.

https://sleeplessbeastie.eu/2018/12/31/how-to-disable-onboard-wifi-and-bluetooth-on-raspberry-pi-3/

Edit your /boot/config.txt and add:
```
dtoverlay=disable-wifi
dtoverlay=disable-bt
```
- The linked page above uses pi3-disable-foo, which are deprecated names
Disable hciuart daemon used for bluetooth modem access
```
systemctl disable --now hciuart
```
Reboot I guess
Edit /etc/pam.d/sshd and remove user_readenv=1, this will keep the logs tidy

Config vim

cat <<EOF > ~/.vimrc
set nocompatible
syntax on
set background=dark
set hlsearch
set modeline
set scrolloff=3
EOF

Config shell

Edit /root/.bashrc to enable colours.

TFTP server

Install the daemon
```
apt install -y tftpd-hpa
```

Copy your stuff into /src/tftp

root@illustrious:~# tree /srv/tftp
/srv/tftp
├── BOOTX64.EFI
├── default.efi
├── grub
│   ├── grub.cfg
│   ├── grub.cfg-01-64-00-6a-70-e6-73 -> persica3
│   ├── grub.cfg-01-64-00-6a-78-50-ed -> persica2
│   ├── grub.cfg-01-98-90-96-be-89-52 -> persica1
│   ├── grubx64.efi
│   ├── persica1
│   ├── persica2
│   └── persica3
├── images
│   └── Alma-9.1
│       ├── initrd.img
│       └── vmlinuz
├── ipxe.efi
└── shimx64.efi

3 directories, 14 files

make an ssh keypair
```
ssh-keygen -t ed25519
```
Dump your key onto the source server then steal its data
Grab updated Alma 9.2 kernel and initrd from here: https://almalinux.mirror.digitalpacific.com.au/9.2/BaseOS/x86_64/kickstart/images/pxeboot/initrd.img
- Drop them in /srv/tftp/images/Alma-9.2/

HTTP server

We need to serve the kickstart files via HTTP.

apt install -y micro-httpd
mkdir /var/www/html/ks
copy the kickstart files in there: rsync -avx illustrious:/data/www/illustrious/ks/ /var/www/html/ks/

Prepare to run rancher

Install docker engine: https://docs.docker.com/engine/install/debian/#install-using-the-repository

curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg
chmod 0644 /etc/apt/keyrings/docker.gpg

cat <<EOF > /etc/apt/sources.list.d/docker.sources
X-Repolib-Name: Docker
Enabled: yes
Types: deb
URIs: https://download.docker.com/linux/debian
Suites: bookworm
Architectures: arm64
Components: stable
Signed-By: /etc/apt/keyrings/docker.gpg
EOF

apt update

# Find versions
apt-cache madison docker-ce | awk '{ print $3 }'

# Install desired
VERSION_STRING="5:23.0.6-1~debian.12~bookworm"
apt install docker-ce=$VERSION_STRING docker-ce-cli=$VERSION_STRING containerd.io

docker run hello-world

Prep certs: https://ranchermanager.docs.rancher.com/pages-for-subheaders/rancher-on-a-single-node-with-docker#option-c-bring-your-own-certificate-signed-by-a-recognized-ca

rsync -avx root@illustrious:/etc/ssl/STAR_thighhighs_top.key /etc/ssl/
etc for the other files

Run rancher container according to this note about using ARM systems: https://ranchermanager.docs.rancher.com/how-to-guides/advanced-user-guides/enable-experimental-features/rancher-on-arm64

docker run -d --restart=unless-stopped \
  -p 443:443 \
  -v /etc/ssl/STAR_thighhighs_top.crtbundled:/etc/rancher/ssl/cert.pem \
  -v /etc/ssl/STAR_thighhighs_top.key:/etc/rancher/ssl/key.pem \
  --privileged \
  rancher/rancher:v2.7.9 \
  --no-cacerts

Fucking cgroups, k3s dies instantly:

EDITOR=vim systemctl edit docker.service

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=cgroupfs

Real answer here: https://github.com/rancher/rancher/issues/36165

systemctl revert docker.service
append to /boot/cmdline.txt:
cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory systemd.unified_cgroup_hierarchy=false systemd.legacy_systemd_cgroup_controller=false

and reboot

Eugh still not running:

2023/11/08 16:56:05 [INFO] Waiting for server to become available: the server is currently unable to handle the request
2023/11/08 16:56:07 [INFO] Waiting for server to become available: the server is currently unable to handle the request
2023/11/08 16:56:19 [INFO] Running in single server mode, will not peer connections
2023/11/08 16:56:19 [INFO] Applying CRD features.management.cattle.io
2023/11/08 16:56:20 [INFO] Waiting for CRD features.management.cattle.io to become available
2023/11/08 16:56:20 [INFO] Done waiting for CRD features.management.cattle.io to become available
2023/11/08 16:56:21 [FATAL] k3s exited with: exit status 1


root@asval:~# less -S k3s.log
I1108 16:56:20.763603      52 cpu_manager.go:214] "Starting CPU manager" policy="none"
I1108 16:56:20.763761      52 cpu_manager.go:215] "Reconciling" reconcilePeriod="10s"
I1108 16:56:20.763895      52 state_mem.go:36] "Initialized new in-memory state store"
I1108 16:56:20.784356      52 policy_none.go:49] "None policy: Start"
E1108 16:56:20.796489      52 nodelease.go:49] "Failed to get node when trying to set owner ref to the node lease" err="nodes \"local-node\" not found" node="local-node"
I1108 16:56:20.804858      52 memory_manager.go:169] "Starting memorymanager" policy="None"
I1108 16:56:20.809257      52 state_mem.go:35] "Initializing new in-memory state store"
I1108 16:56:20.846809      52 kubelet_node_status.go:73] "Successfully registered node" node="local-node"
E1108 16:56:20.866904      52 kubelet.go:1466] "Failed to start ContainerManager" err="failed to get rootfs info: unable to find data in memory cache"

Is it because asval only has 1gb RAM?

Build the nodes

This just works now, huzzah! Manually kick the BIOS of each node to do a one-time PXE boot, then let it do its thing.

Node configs

Salvage my old ansible playbook stuff and copy it to asval. Run it from there.

apt install -y ansible sshpass

cd ~/git/persica-ansible/
make persica ARGS="-C --tags common"

k8s notes

Make a simple 3-node cluster
Single-node control plane will run externally, on illustrious
Use kubeadm to build the cluster: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
Selected containerd as the container runtime
Will use Flannel as the networking plugin
Allocated IPs:
- persica1 / 192.168.1.31
- persica2 / 192.168.1.32
- persica3 / 192.168.1.33
Ingress: undecided so far
Cgroup driver: let's use systemd
k8s version: whatever is latest right now (2023-04-04)

Build notes

Per node

Update the BIOS using this guide: https://www.dell.com/support/kbdoc/en-au/000131486/update-the-dell-bios-in-a-linux-or-ubuntu-environment#updatebios2015
- Despite the usual Dell docs saying you need to make a DOS boot disk and run the flash updater app from there, it turns out that the BIOS Flash Update target (mash F12 to get the one-time boot menu) can read the 9020MA19.exe file from a FAT32 filesystem on a USB stick just fine
- Not sure if this only works in UEFI mode or not, but I kinda don't care because we want to be in UEFI mode
- This applies to systems made from 2015 or later
- The latest BIOS update for the Optiplex 9020M is version A19, released
Set BIOS to full UEFI mode, no legacy
We'll be using DHCP, so find the MAC address so we can give it a consistent IP address when it boots
Add the MAC address and IP assignment to dnsmasq on calico (a pihole box)
- /etc/dnsmasq.d/02-pihole-dhcp-persica-cluster.conf
- Something like this
```
dhcp-host=98:90:96:BE:89:52,set:persica,192.168.1.31,persica1,5m
# one dhcp-host line per host
dhcp-boot=tag:persica,grub/grubx64.efi,illustrious.thighhighs.top,192.168.1.12
```
- Run pihole restartdns after making changes
PXE boot for kickstart install, which will hit calico for DHCP, then illustrious for the boot image and kickstart config

tftpd-hpa is running on illustrious

Upstream repo mirror: https://repo.almalinux.org/almalinux/9/BaseOS/x86_64/os/EFI/BOOT/

Drop that content in /srv/tftp/

root@illustrious:/srv/tftp# tree
.
├── BOOTX64.EFI
├── default.efi
├── grub
│   ├── grub.cfg
│   ├── grub.cfg-01-98-90-96-be-89-52
│   └── grubx64.efi
├── images
│   └── Alma-9.1
│       ├── initrd.img
│       └── vmlinuz
├── ipxe.efi
└── shimx64.efi

Add a grub config fragment for the host's MAC address: grub.cfg-01-xx-xx-xx-xx-xx-xx
Make sure the grub config has the correct URL for its kickstart config

kickstart file served from /data/www/illustrious/ks: https://illustrious.thighhighs.top/ks/persica1.ks.cfg
- Make sure your per-host config file has the correct name
KS references:
- Reference manual: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/performing_an_advanced_rhel_9_installation/kickstart-commands-and-options-reference_installing-rhel-as-an-experienced-user#keyboard-required_kickstart-commands-for-system-configuration
- Generator tool: https://access.redhat.com/labs/kickstartconfig/
k8s doesn't play well with swap so we need to disable it. Provision a minimal swap volume of 1gb, then disable it later

This was useful for figuring out the TFTP stuff for the first time: https://askubuntu.com/questions/1183487/grub2-efi-boot-via-pxe-load-config-file-automatically

Paths are hardcoded into the grubx64.efi binary, meaning HDD and PXE versions aren't the same. Make sure you put all the grub stuff in a grub/ directory. Check the $prefix to see where it's searching:

UEFI settings

Get to the UEFI

Probably get stuck in windows for first boot
Win, then "UEFI", get to advanced startup options
Boot with Advanced Boot Options
Troubleshoot, Advanced Options, UEFI Firmware Settings, Restart

Record details

Get the LOM MAC Address from Settings, General, System Info

Change settings

General
- Boot Sequence
  - Select UEFI boot list
- Advanced Boot Options
  - Disable Legacy OPROMs
- UEFI Boot Path Security
  - Set to Never
- Date/Time
  - Set clock to approx correct for UTC time
System Configuration
- Integrated NIC
  - Enable UEFI Network Stack
  - Enabled w/ PXE
- SATA Operation
  - AHCI
- SMART Reporting
  - Disabled, we don't need it
- Audio
  - Disable all audio, we don't need it
Security
- TPM Security
  - Check everything except Clear
  - Activated
- CPU XD support
  - Enabled
Secure Boot
- Secure Boot Enable
  - Disabled
Performance
- Multi-core support: All
- Speedstep: Enabled
- C-states: Enabled
- Limit CPUID: Disabled
- Turboboost: Enabled
Power Management
- AC Recovery: Power On
- Deep Sleep Control: Disabled
- USB Wake Support: Enable USB wake from Standby
- Wake on LAN/WLAN: LAN with PXE Boot
- Block Sleep: Enable blocking of sleep
POST Behaviour
- Keyboard Errors: Disable error detection
Virtualisation support
- Enable VT
- Enable VT-d
- Enable Trusted Execution

Reboot and go back in again.

Boot only from IPv4 with NIC (PXE boot)

Ansible management after kickstart build

This is getting everything to the state where I can bootstrap the cluster. I should ansible'ise everything, making minimal assumptions about the kickstart part of the process.

I'm keeping a simple ansible repo in ~/git/persica-ansible/

I have a basic set of roles to get the nodes into a workable state, right before I invoke kubeadm for the first time.

---
- name: Configure persica k8s cluster
  hosts: persica
  roles:
    - role: common
      tags: common
    - role: docker_for_kube
      tags: docker_for_kube
    - role: kube_daemons
      tags: kube_daemons

Initialise the control plane

This is manual of course, no ansible here.

https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/#initializing-your-control-plane-node

This will be a single-node control plane, but we should specify --control-plane-endpoint anyway. persica1 is going to be our control plane.
Our Pod network add-on will be Flannel. We can specify --pod-network-cidr but I'll try without first.
It'll detect containerd
The default --apiserver-advertise-address will be fine, let it autodetect

I added a custom CNAME record to local pihole (calico) and Gandi (public service), for persica-endpoint => persica1. Unlike the DHCP stuff, this is in the general DNS web interface, not a custom config file.

After a bunch of faffing around to fix up the firewall config, bridge filtering kernel module, and enabling ipv4 forwarding, the init begins after passing preflight checks.

[root@persica1 ~]# kubeadm init --control-plane-endpoint=persica-endpoint
[init] Using Kubernetes version: v1.27.1
[preflight] Running pre-flight checks
        [WARNING Firewalld]: firewalld is active, please ensure ports [6443 10250] are open or your cluster may not function correctly
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
W0415 03:43:19.958609   39430 images.go:80] could not find officially supported version of etcd for Kubernetes v1.27.1, falling back to the nearest etcd version (3.5.7-0)
W0415 03:43:52.646765   39430 checks.go:835] detected that the sandbox image "registry.k8s.io/pause:3.6" of the container runtime is inconsistent with that used by kubeadm. It is recommended that using "registry.k8s.io/pause:3.9" as the CRI sandbox image.
[certs] Using certificateDir folder "/etc/kubernetes/pki"
[certs] Generating "ca" certificate and key
[certs] Generating "apiserver" certificate and key
[certs] apiserver serving cert is signed for DNS names [kubernetes kubernetes.default kubernetes.default.svc kubernetes.default.svc.cluster.local persica-endpoint persica1] and IPs [10.96.0.1 192.168.1.31]
[certs] Generating "apiserver-kubelet-client" certificate and key
[certs] Generating "front-proxy-ca" certificate and key
[certs] Generating "front-proxy-client" certificate and key
[certs] Generating "etcd/ca" certificate and key
[certs] Generating "etcd/server" certificate and key
[certs] etcd/server serving cert is signed for DNS names [localhost persica1] and IPs [192.168.1.31 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost persica1] and IPs [192.168.1.31 127.0.0.1 ::1]
[certs] Generating "etcd/healthcheck-client" certificate and key
[certs] Generating "apiserver-etcd-client" certificate and key
[certs] Generating "sa" key and public key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Starting the kubelet
[control-plane] Using manifest folder "/etc/kubernetes/manifests"
[control-plane] Creating static Pod manifest for "kube-apiserver"
[control-plane] Creating static Pod manifest for "kube-controller-manager"
[control-plane] Creating static Pod manifest for "kube-scheduler"
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
W0415 03:44:21.781505   39430 images.go:80] could not find officially supported version of etcd for Kubernetes v1.27.1, falling back to the nearest etcd version (3.5.7-0)
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests". This can take up to 4m0s
[kubelet-check] Initial timeout of 40s passed.

Unfortunately, an error has occurred:
        timed out waiting for the condition

This error is likely caused by:
        - The kubelet is not running
        - The kubelet is unhealthy due to a misconfiguration of the node in some way (required cgroups disabled)

If you are on a systemd-powered system, you can try to troubleshoot the error with the following commands:
        - 'systemctl status kubelet'
        - 'journalctl -xeu kubelet'

Additionally, a control plane component may have crashed or exited when started by the container runtime.
To troubleshoot, list all containers using your preferred container runtimes CLI.
Here is one example how you may list all running Kubernetes containers by using crictl:
        - 'crictl --runtime-endpoint unix:///var/run/containerd/containerd.sock ps -a | grep kube | grep -v pause'
        Once you have found the failing container, you can inspect its logs with:
        - 'crictl --runtime-endpoint unix:///var/run/containerd/containerd.sock logs CONTAINERID'
error execution phase wait-control-plane: couldn't initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher

No worky :/

https://serverfault.com/questions/1116281/kubeadm-1-25-init-failed-on-debian-11-with-containerd-connection-refused

Maybe I need the control plane on a separate node after all. I'll try illustrious.

copy containerd/config.toml to illustrious
apt install -y apt-transport-https ca-certificates curl
curl -fsSLo /etc/apt/trusted.gpg.d/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg

prep repo defn

cat <<EOF > /etc/apt/sources.list.d/kubernetes.sources
X-Repolib-Name: Kubernetes
Enabled: yes
Types: deb
URIs: https://apt.kubernetes.io/
Suites: kubernetes-xenial
Architectures: amd64
Components: main
Signed-By: /etc/apt/trusted.gpg.d/kubernetes-archive-keyring.gpg
X-Repolib-ID: Kubernetes
EOF

apt update
apt install -y kubelet kubeadm kubectl
apt-mark hold kubelet kubeadm kubectl

Now try kubeadm again.

Oh sonovabitch! Config not well described: https://github.com/containerd/containerd/issues/6964

Fixed config /etc/containerd/config.toml:

version = 2

disabled_plugins = []

[plugins."io.containerd.grpc.v1.cri".containerd.runtimes]

  [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
    base_runtime_spec = ""
    cni_conf_dir = ""
    cni_max_conf_num = 0
    container_annotations = []
    pod_annotations = []
    privileged_without_host_devices = false
    runtime_engine = ""
    runtime_path = ""
    runtime_root = ""
    runtime_type = "io.containerd.runc.v2"

  [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
    BinaryName = ""
    CriuImagePath = ""
    CriuPath = ""
    CriuWorkPath = ""
    IoGid = 0
    IoUid = 0
    NoNewKeyring = false
    NoPivotRoot = false
    Root = ""
    ShimCgroup = ""
    SystemdCgroup = true

# They suggest pinning this image, so we'll do that. This is the out-of-box default.
# https://kubernetes.io/docs/setup/production-environment/container-runtimes/#override-pause-image-containerd
[plugins."io.containerd.grpc.v1.cri"]
  sandbox_image = "registry.k8s.io/pause:3.9"

We could/should be using kubeadm init with a configuration file: https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/

Apr 15 04:48:26 illustrious.thighhighs.top systemd[1]: Started kubelet: The Kubernetes Node Agent.
Apr 15 04:48:26 illustrious.thighhighs.top kubelet[12354]: Flag --container-runtime-endpoint has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.
Apr 15 04:48:26 illustrious.thighhighs.top kubelet[12354]: Flag --pod-infra-container-image has been deprecated, will be removed in a future release. Image garbage collector will get sandbox image information from CRI.

But screw that. Because guess what, it's also poorly documented!

Initialising the control plane now actually works

kubeadm init --control-plane-endpoint=persica-endpoint

Setup my `~/.kube/` config stuff as directed. Apparently this is an uber-superuser, so I shouldn't be using it regularly. Oh.

cat <<EOF > kubeconfig_example.yml
apiVersion: kubeadm.k8s.io/v1beta3
kind: ClusterConfiguration
# Will be used as the target "cluster" in the kubeconfig
clusterName: "persica"
# Will be used as the "server" (IP or DNS name) of this cluster in the kubeconfig
controlPlaneEndpoint: "persica-endpoint.thighhighs.top:6443"
# The cluster CA key and certificate will be loaded from this local directory
certificatesDir: "/etc/kubernetes/pki"
EOF

# on illustrious
kubeadm kubeconfig user --config kubeconfig_example.yml --client-name furinkan --validity-period 8760h

Now try adding a pod network. We'll use Flannel, and find the docs ourselves: https://github.com/flannel-io/flannel#deploying-flannel-manually

# from suomi
kubectl --context=persica-admin apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml

kubectl --context=persica-admin get pods --all-namespaces
NAMESPACE      NAME                                                 READY   STATUS              RESTARTS      AGE
kube-flannel   kube-flannel-ds-zr6fb                                0/1     CrashLoopBackOff    1 (16s ago)   34s
kube-system    coredns-5d78c9869d-mp7p9                             0/1     ContainerCreating   0             66m
kube-system    coredns-5d78c9869d-tlsc6                             0/1     ContainerCreating   0             66m
kube-system    etcd-illustrious.thighhighs.top                      1/1     Running             1             66m
kube-system    kube-apiserver-illustrious.thighhighs.top            1/1     Running             1             66m
kube-system    kube-controller-manager-illustrious.thighhighs.top   1/1     Running             1             66m
kube-system    kube-proxy-5mntm                                     1/1     Running             0             66m
kube-system    kube-scheduler-illustrious.thighhighs.top            1/1     Running             1             66m

Doesn't work because we don't have the same podCIDR, and the default isn't compatible with whatever kubeadm does? FFS!

https://devops.stackexchange.com/questions/5898/how-to-get-kubernetes-pod-network-cidr

Okay so I can either nuke the cluster and reinstantiate it with podCIDR, or just reinstall the network plugin or something. Let's try the latter.

get the current podCIDR: https://devops.stackexchange.com/a/14867
kubeadm config print init-defaults | grep serviceSubnet
wget https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml
Edit it
Reapply it? kubectl apply -f kube-flannel.yml
Is it still crashlooping? kubectl get pods --all-namespaces

Yeah.

Fukkit try again

# on illustrious
kubeadm reset
rm -rf /etc/cni/net.d/
rm -rf ~/.kube/

# fix the init: https://github.com/flannel-io/flannel/issues/728#issuecomment-308878912
kubeadm init --control-plane-endpoint=persica-endpoint.thighhighs.top --pod-network-cidr=10.244.0.0/16

# Fix up my kubectl creds again

# install flannel again
kubectl apply -f https://github.com/flannel-io/flannel/releases/latest/download/kube-flannel.yml

# is it working now?
kubectl get pods --all-namespaces

# IT FUCKING WORKS!!

Now we join some worker nodes to the cluster, finally.

# on persica1
kubeadm join persica-endpoint.thighhighs.top:6443 --token FOO.FOOFOOFOO \
        --discovery-token-ca-cert-hash sha256:BARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBARBAR

[preflight] Running pre-flight checks
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Starting the kubelet
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...

This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.

Run 'kubectl get nodes' on the control-plane to see this node join the cluster.

It's joined but apparently NotReady:

root@illustrious:~# kubectl get nodes
NAME                         STATUS     ROLES           AGE    VERSION
illustrious.thighhighs.top   NotReady   control-plane   17m    v1.27.1
persica1                     NotReady   <none>          2m7s   v1.27.0

Apparently coredns won't start because of taints, as described here:

https://serverfault.com/questions/1064936/coredns-pods-stuck-in-pending-state
- No explanation as to why the taints aren't going away
Similar problem here
- Someone says to just restart containerd

Fuck yoooooouuu, now the coredns containers are running. I probably shouldn't have jumped the gun and joined all the worker nodes... I need to kick them so they start properly.

root@illustrious:~# kubectl get pods --all-namespaces
NAMESPACE      NAME                                                 READY   STATUS              RESTARTS   AGE
kube-flannel   kube-flannel-ds-4p4wd                                0/1     Init:0/2            0          21m
kube-flannel   kube-flannel-ds-6qfrm                                0/1     Init:0/2            0          12m
kube-flannel   kube-flannel-ds-kb94w                                0/1     Init:0/2            0          12m
kube-flannel   kube-flannel-ds-vctrt                                1/1     Running             0          30m
kube-system    coredns-5d78c9869d-dqnkh                             1/1     Running             0          36m
kube-system    coredns-5d78c9869d-rbmhm                             1/1     Running             0          36m
kube-system    etcd-illustrious.thighhighs.top                      1/1     Running             2          36m
kube-system    kube-apiserver-illustrious.thighhighs.top            1/1     Running             2          36m
kube-system    kube-controller-manager-illustrious.thighhighs.top   1/1     Running             0          36m
kube-system    kube-proxy-8dl56                                     0/1     ContainerCreating   0          12m
kube-system    kube-proxy-dppxt                                     0/1     ContainerCreating   0          21m
kube-system    kube-proxy-ljk6c                                     1/1     Running             0          36m
kube-system    kube-proxy-t7gcn                                     0/1     ContainerCreating   0          12m
kube-system    kube-scheduler-illustrious.thighhighs.top            1/1     Running             2          36m

Try deleting and re-adding a node. From https://stackoverflow.com/a/54220808/806927

# on illustrious
kubectl get nodes
kubectl drain persica1
kubectl drain persica1 --ignore-daemonsets --delete-local-data
kubectl delete node persica1

# on persica1
kubeadm reset

then join again

Looks like the kube-proxy is having trouble starting on persica1. And while it's only a warning, I bet it's more significant than that.

root@illustrious:~# kubectl get pods --all-namespaces
NAMESPACE      NAME                                                 READY   STATUS              RESTARTS   AGE
kube-flannel   kube-flannel-ds-gjq5h                                0/1     Init:0/2            0          3m33s
kube-flannel   kube-flannel-ds-vctrt                                1/1     Running             0          41m
kube-system    coredns-5d78c9869d-dqnkh                             1/1     Running             0          47m
kube-system    coredns-5d78c9869d-rbmhm                             1/1     Running             0          47m
kube-system    etcd-illustrious.thighhighs.top                      1/1     Running             2          47m
kube-system    kube-apiserver-illustrious.thighhighs.top            1/1     Running             2          47m
kube-system    kube-controller-manager-illustrious.thighhighs.top   1/1     Running             0          47m
kube-system    kube-proxy-ljk6c                                     1/1     Running             0          47m
kube-system    kube-proxy-xpv58                                     0/1     ContainerCreating   0          3m33s
kube-system    kube-scheduler-illustrious.thighhighs.top            1/1     Running             2          47m

root@illustrious:~# kubectl get events --namespace=kube-system | grep pod/kube-proxy-xpv58
4m29s       Normal    Scheduled                pod/kube-proxy-xpv58   Successfully assigned kube-system/kube-proxy-xpv58 to persica1
9s          Warning   FailedCreatePodSandBox   pod/kube-proxy-xpv58   Failed to create pod sandbox: open /run/systemd/resolve/resolv.conf: no such file or directory


# on persica1
mkdir /run/systemd/resolve
ln -s /etc/resolv.conf /run/systemd/resolve/resolv.conf

wtf now there's another error:

root@illustrious:~# kubectl get events --namespace=kube-system | grep pod/kube-proxy-grqhf
20s         Normal    Scheduled                pod/kube-proxy-grqhf   Successfully assigned kube-system/kube-proxy-grqhf to persica1
6s          Warning   FailedCreatePodSandBox   pod/kube-proxy-grqhf   Failed to create pod sandbox: rpc error: code = InvalidArgument desc = failed to create containerd container: create container failed validation: container.Runtime.Name must be set: invalid argument

I think I haven't deployed a good containerd config everywhere yet. Deployed that, and suddenly the damn kube-proxy and kube-flannel containers are working.

Now I can add the other two nodes, still need to fix the resolv.conf manually.

root@illustrious:~# kubectl get nodes -o wide
NAME                         STATUS   ROLES           AGE     VERSION   INTERNAL-IP    EXTERNAL-IP   OS-IMAGE                    KERNEL-VERSION                CONTAINER-RUNTIME
illustrious.thighhighs.top   Ready    control-plane   78m     v1.27.1   192.168.1.12   <none>        Ubuntu 22.04.2 LTS          5.15.0-69-generic             containerd://1.6.20
persica1                     Ready    <none>          21m     v1.27.0   192.168.1.31   <none>        AlmaLinux 9.1 (Lime Lynx)   5.14.0-162.6.1.el9_1.x86_64   containerd://1.6.20
persica2                     Ready    <none>          2m41s   v1.27.0   192.168.1.32   <none>        AlmaLinux 9.1 (Lime Lynx)   5.14.0-162.6.1.el9_1.x86_64   containerd://1.6.20
persica3                     Ready    <none>          33s     v1.27.0   192.168.1.33   <none>        AlmaLinux 9.1 (Lime Lynx)   5.14.0-162.6.1.el9_1.x86_64   containerd://1.6.20

Good enough for now!

Making ingress work

I don't understand this well enough, but I want to use ingress-nginx. Here's a page about it, albeit not using raw kubectl: https://kubernetes.github.io/ingress-nginx/kubectl-plugin/

Maybe this one too: https://medium.com/tektutor/using-nginx-ingress-controller-in-kubernetes-bare-metal-setup-890eb4e7772

Making load balancing work

I thought I wouldn't need it, but it looks like I do, if I want sensible useful functionality. Here's an explanation of why I want to use Metal LB, and it's not just for BGP-based configs: https://github.com/kubernetes/ingress-nginx/blob/main/docs/deploy/baremetal.md

I'll use it in L2 mode with ARP/NDP I think. Just need to dedicate a bunch of IPs to it so it can manage the traffic to them.

-  ⇤ ← Revision 14 as of 2023-04-15 19:07:03 → 
  Size: 25742
  Editor: furinkan
  Comment: all nodes in the cluster now
+   ← Revision 23 as of 2023-11-08 17:03:04 → ⇥
  Size: 36147
  Editor: furinkan
  Comment: rancher won't run yet
-Deletions are marked like this.
+Additions are marked like this.
 Line 11:
+{{{#!wiki note
I last touched this in April 2023 and it was very annoying to get as far as I did. Next time I look at it, I think I will rebuild the cluster from scratch again, and use a different guide. Something with actual explanations and a few opinions, like this one: https://github.com/hobby-kube/guide
}}}
-Line 12:
+Line 16:
+== Another rebuild attempt in late 2023 ==

A few changes for this one:
 * I'm going to use Rancher this time, or that guide linked above
 * Alma 9.2 because it's the latest
 * Move them to the "subnet" of 192.168.1.32/29 so I can configure the router to give them DHCP options easily
  * persica1 / 192.168.1.33
  * persica2 / 192.168.1.34
  * persica3 / 192.168.1.35
 * Put the controller node onto asval rather than illustrious, which in this case might be the rancher docker container
  * asval / 192.168.1.32 (should probably be a static IP)
  * persica / CNAME to asval
 * Go with Longhorn for PVCs
 * Dunno what to do about ingress yet

=== Prepare asval controller node ===

==== OS imaging ====
Using the Raspberry Pi Imager app, start with RPi OS Lite 64-bit, suitable for the RPi 3B+

It lets you make some customisations before flashing, which is really nice:
 * Set hostname to asval
 * Enable SSH
  * Password auth (I would use SSH but it didn't work right for me and I couldn't sudo later)
 * Set username and password
  * `pi // <something new>`
 * No WLAN
 * Set locale to Australia/Sydney, us keyboard
 * Disable telemetry

==== Config ====

 * Login as `pi@asval` and copy your SSH key there
 * Install base packages {{{
apt install -y vim git screen ack
}}}
 * Enable I2C bus for the RTC
  * Run `raspi-config`
   * Interface Options -> I2C -> Enable
  * `dtparam=i2c_arm=on` has already been enabled in `/boot/config.txt` for us
  * i2c_dev module should now/already be loaded so we're ready to go I hope
  * Reboot now, it can't hurt
 * Install i2c tools {{{
apt install -y i2c-tools
}}}
 * Detect the device on i2c bus: `i2cdetect -y 1`
  * Should appear at 0x68
 * Enable the kernel driver for it, or something, by adding a devicetree overlay. Append this to the end of /boot/config.txt {{{
dtoverlay=i2c-rtc,ds3231
}}}
 * Reboot again to load the device tree overlay that we just configured
 * Again detect the device on i2c bus: `i2cdetect -y 1`
  * Should appear at 0x68, BUT with "UU" at the address this time
 * Remove the fake hardware clock {{{
systemctl disable fake-hwclock --now
apt purge -y fake-hwclock
}}}
 * In theory everything just works now thanks to a udev rule: https://www.raspberrypi.org/forums/viewtopic.php?t=209700 {{{
root@asval:~# cat /lib/udev/rules.d/85-hwclock.rules
# Set the System Time from the Hardware Clock and set the kernel's timezone
# value to the local timezone when the kernel clock module is loaded.
KERNEL=="rtc0", RUN+="/usr/lib/udev/hwclock-set $root/$name"
}}}
 * Install chrony so it manages the hardware clock {{{
apt install -y chrony
}}} It'll do the rest once it's installed and synced. Try some commands to see how it's fairing: {{{
chronyc sources
chronyc tracking
}}}


==== Disable unneeded stuff ====

I'm using asval as a network appliance, so I don't need the wifi and bluetooth radios.

https://sleeplessbeastie.eu/2018/12/31/how-to-disable-onboard-wifi-and-bluetooth-on-raspberry-pi-3/

 1. Edit your `/boot/config.txt` and add: {{{
dtoverlay=disable-wifi
dtoverlay=disable-bt
}}}
  * The linked page above uses pi3-disable-foo, which are deprecated names
 1. Disable hciuart daemon used for bluetooth modem access {{{
systemctl disable --now hciuart
}}}
 1. Reboot I guess
 1. Edit `/etc/pam.d/sshd` and remove `user_readenv=1`, this will keep the logs tidy

==== Config vim ====
{{{
cat <<EOF > ~/.vimrc
set nocompatible
syntax on
set background=dark
set hlsearch
set modeline
set scrolloff=3
EOF
}}}

==== Config shell ====
Edit `/root/.bashrc` to enable colours.


==== TFTP server ====

 * Install the daemon {{{
apt install -y tftpd-hpa
}}}
 * Copy your stuff into `/src/tftp` {{{
root@illustrious:~# tree /srv/tftp
/srv/tftp
├── BOOTX64.EFI
├── default.efi
├── grub
│   ├── grub.cfg
│   ├── grub.cfg-01-64-00-6a-70-e6-73 -> persica3
│   ├── grub.cfg-01-64-00-6a-78-50-ed -> persica2
│   ├── grub.cfg-01-98-90-96-be-89-52 -> persica1
│   ├── grubx64.efi
│   ├── persica1
│   ├── persica2
│   └── persica3
├── images
│   └── Alma-9.1
│       ├── initrd.img
│       └── vmlinuz
├── ipxe.efi
└── shimx64.efi

3 directories, 14 files
}}}
 * make an ssh keypair {{{
ssh-keygen -t ed25519
}}}
 * Dump your key onto the source server then steal its data
 * Grab updated Alma 9.2 kernel and initrd from here: https://almalinux.mirror.digitalpacific.com.au/9.2/BaseOS/x86_64/kickstart/images/pxeboot/initrd.img
  * Drop them in `/srv/tftp/images/Alma-9.2/`

==== HTTP server ====

We need to serve the kickstart files via HTTP.
 * apt install -y micro-httpd
 * mkdir /var/www/html/ks
 * copy the kickstart files in there: rsync -avx illustrious:/data/www/illustrious/ks/ /var/www/html/ks/


==== Prepare to run rancher ====

Install docker engine: https://docs.docker.com/engine/install/debian/#install-using-the-repository
{{{
curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /etc/apt/keyrings/docker.gpg
chmod 0644 /etc/apt/keyrings/docker.gpg

cat <<EOF > /etc/apt/sources.list.d/docker.sources
X-Repolib-Name: Docker
Enabled: yes
Types: deb
URIs: https://download.docker.com/linux/debian
Suites: bookworm
Architectures: arm64
Components: stable
Signed-By: /etc/apt/keyrings/docker.gpg
EOF

apt update

# Find versions
apt-cache madison docker-ce | awk '{ print $3 }'

# Install desired
VERSION_STRING="5:23.0.6-1~debian.12~bookworm"
apt install docker-ce=$VERSION_STRING docker-ce-cli=$VERSION_STRING containerd.io

docker run hello-world
}}}

Prep certs: https://ranchermanager.docs.rancher.com/pages-for-subheaders/rancher-on-a-single-node-with-docker#option-c-bring-your-own-certificate-signed-by-a-recognized-ca
{{{
rsync -avx root@illustrious:/etc/ssl/STAR_thighhighs_top.key /etc/ssl/
etc for the other files
}}}

Run rancher container according to this note about using ARM systems: https://ranchermanager.docs.rancher.com/how-to-guides/advanced-user-guides/enable-experimental-features/rancher-on-arm64
{{{
docker run -d --restart=unless-stopped \
  -p 443:443 \
  -v /etc/ssl/STAR_thighhighs_top.crtbundled:/etc/rancher/ssl/cert.pem \
  -v /etc/ssl/STAR_thighhighs_top.key:/etc/rancher/ssl/key.pem \
  --privileged \
  rancher/rancher:v2.7.9 \
  --no-cacerts
}}}

Fucking cgroups, k3s dies instantly:
 * https://github.com/rancher/rancher/issues/35201#issuecomment-947331154
 * https://groups.google.com/g/linux.debian.bugs.dist/c/Z-Cc0WmlEGA/m/NB6XGDsnAwAJ
{{{
EDITOR=vim systemctl edit docker.service

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock --exec-opt native.cgroupdriver=cgroupfs
}}}
Real answer here: https://github.com/rancher/rancher/issues/36165
{{{
systemctl revert docker.service
append to /boot/cmdline.txt:
cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory systemd.unified_cgroup_hierarchy=false systemd.legacy_systemd_cgroup_controller=false
}}} and reboot

Eugh still not running: {{{
2023/11/08 16:56:05 [INFO] Waiting for server to become available: the server is currently unable to handle the request
2023/11/08 16:56:07 [INFO] Waiting for server to become available: the server is currently unable to handle the request
2023/11/08 16:56:19 [INFO] Running in single server mode, will not peer connections
2023/11/08 16:56:19 [INFO] Applying CRD features.management.cattle.io
2023/11/08 16:56:20 [INFO] Waiting for CRD features.management.cattle.io to become available
2023/11/08 16:56:20 [INFO] Done waiting for CRD features.management.cattle.io to become available
2023/11/08 16:56:21 [FATAL] k3s exited with: exit status 1


root@asval:~# less -S k3s.log
I1108 16:56:20.763603      52 cpu_manager.go:214] "Starting CPU manager" policy="none"
I1108 16:56:20.763761      52 cpu_manager.go:215] "Reconciling" reconcilePeriod="10s"
I1108 16:56:20.763895      52 state_mem.go:36] "Initialized new in-memory state store"
I1108 16:56:20.784356      52 policy_none.go:49] "None policy: Start"
E1108 16:56:20.796489      52 nodelease.go:49] "Failed to get node when trying to set owner ref to the node lease" err="nodes \"local-node\" not found" node="local-node"
I1108 16:56:20.804858      52 memory_manager.go:169] "Starting memorymanager" policy="None"
I1108 16:56:20.809257      52 state_mem.go:35] "Initializing new in-memory state store"
I1108 16:56:20.846809      52 kubelet_node_status.go:73] "Successfully registered node" node="local-node"
E1108 16:56:20.866904      52 kubelet.go:1466] "Failed to start ContainerManager" err="failed to get rootfs info: unable to find data in memory cache"
}}}

Is it because asval only has 1gb RAM?



=== Build the nodes ===

This just works now, huzzah! Manually kick the BIOS of each node to do a one-time PXE boot, then let it do its thing.

=== Node configs ===

Salvage my old ansible playbook stuff and copy it to asval. Run it from there.

{{{
apt install -y ansible sshpass

cd ~/git/persica-ansible/
make persica ARGS="-C --tags common"
}}}
-Line 509:
+Line 771:
+== Making ingress work ==

I don't understand this well enough, but I want to use ingress-nginx. Here's a page about it, albeit not using raw kubectl: https://kubernetes.github.io/ingress-nginx/kubectl-plugin/

Maybe this one too: https://medium.com/tektutor/using-nginx-ingress-controller-in-kubernetes-bare-metal-setup-890eb4e7772

== Making load balancing work ==

I thought I wouldn't need it, but it looks like I do, if I want sensible useful functionality. Here's an explanation of why I want to use Metal LB, and it's not just for BGP-based configs: https://github.com/kubernetes/ingress-nginx/blob/main/docs/deploy/baremetal.md

I'll use it in L2 mode with ARP/NDP I think. Just need to dedicate a bunch of IPs to it so it can manage the traffic to them.

Useful(?) links

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