ControlNode improvements

[danielskowronski]

Before creating an issue, make sure you've checked the following:

• You are running the latest released version of k0s
• Make sure you've searched for existing issues, both open and closed
• Make sure you've searched for PRs too, a fix might've been merged already
• You're looking at docs for the released version, "main" branch docs are usually ahead of released versions.

Platform

Linux 5.15.0-89-generic #99-Ubuntu SMP Mon Oct 30 23:43:36 UTC 2023 aarch64 GNU/Linux
PRETTY_NAME="Ubuntu 22.04.3 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.3 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy

Version

v1.28.3+k0s.0

Sysinfo

k0s sysinfo

Machine ID: "79ddb2e3138db600e33e9e17f99178e3bc2ef854ada28405aea969ce243065ff" (from machine) (pass)
Total memory: 962.3 MiB (warning: 1.0 GiB recommended)
Disk space available for /var/lib/k0s: 2.3 GiB (pass)
Name resolution: localhost: [::1 127.0.0.1] (pass)
Operating system: Linux (pass)
  Linux kernel release: 5.15.0-89-generic (pass)
  Max. file descriptors per process: current: 1048576 / max: 1048576 (pass)
  AppArmor: active (pass)
  Executable in PATH: modprobe: /usr/sbin/modprobe (pass)
  Executable in PATH: mount: /usr/bin/mount (pass)
  Executable in PATH: umount: /usr/bin/umount (pass)
  /proc file system: mounted (0x9fa0) (pass)
  Control Groups: version 2 (pass)
    cgroup controller "cpu": available (pass)
    cgroup controller "cpuacct": available (via cpu in version 2) (pass)
    cgroup controller "cpuset": available (pass)
    cgroup controller "memory": available (pass)
    cgroup controller "devices": available (assumed) (pass)
    cgroup controller "freezer": available (assumed) (pass)
    cgroup controller "pids": available (pass)
    cgroup controller "hugetlb": available (pass)
    cgroup controller "blkio": available (via io in version 2) (pass)
  CONFIG_CGROUPS: Control Group support: built-in (pass)
    CONFIG_CGROUP_FREEZER: Freezer cgroup subsystem: built-in (pass)
    CONFIG_CGROUP_PIDS: PIDs cgroup subsystem: built-in (pass)
    CONFIG_CGROUP_DEVICE: Device controller for cgroups: built-in (pass)
    CONFIG_CPUSETS: Cpuset support: built-in (pass)
    CONFIG_CGROUP_CPUACCT: Simple CPU accounting cgroup subsystem: built-in (pass)
    CONFIG_MEMCG: Memory Resource Controller for Control Groups: built-in (pass)
    CONFIG_CGROUP_HUGETLB: HugeTLB Resource Controller for Control Groups: built-in (pass)
    CONFIG_CGROUP_SCHED: Group CPU scheduler: built-in (pass)
      CONFIG_FAIR_GROUP_SCHED: Group scheduling for SCHED_OTHER: built-in (pass)
        CONFIG_CFS_BANDWIDTH: CPU bandwidth provisioning for FAIR_GROUP_SCHED: built-in (pass)
    CONFIG_BLK_CGROUP: Block IO controller: built-in (pass)
  CONFIG_NAMESPACES: Namespaces support: built-in (pass)
    CONFIG_UTS_NS: UTS namespace: built-in (pass)
    CONFIG_IPC_NS: IPC namespace: built-in (pass)
    CONFIG_PID_NS: PID namespace: built-in (pass)
    CONFIG_NET_NS: Network namespace: built-in (pass)
  CONFIG_NET: Networking support: built-in (pass)
    CONFIG_INET: TCP/IP networking: built-in (pass)
      CONFIG_IPV6: The IPv6 protocol: built-in (pass)
    CONFIG_NETFILTER: Network packet filtering framework (Netfilter): built-in (pass)
      CONFIG_NETFILTER_ADVANCED: Advanced netfilter configuration: built-in (pass)
      CONFIG_NF_CONNTRACK: Netfilter connection tracking support: module (pass)
      CONFIG_NETFILTER_XTABLES: Netfilter Xtables support: module (pass)
        CONFIG_NETFILTER_XT_TARGET_REDIRECT: REDIRECT target support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_COMMENT: "comment" match support: module (pass)
        CONFIG_NETFILTER_XT_MARK: nfmark target and match support: module (pass)
        CONFIG_NETFILTER_XT_SET: set target and match support: module (pass)
        CONFIG_NETFILTER_XT_TARGET_MASQUERADE: MASQUERADE target support: module (pass)
        CONFIG_NETFILTER_XT_NAT: "SNAT and DNAT" targets support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_ADDRTYPE: "addrtype" address type match support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_CONNTRACK: "conntrack" connection tracking match support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_MULTIPORT: "multiport" Multiple port match support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_RECENT: "recent" match support: module (pass)
        CONFIG_NETFILTER_XT_MATCH_STATISTIC: "statistic" match support: module (pass)
      CONFIG_NETFILTER_NETLINK: module (pass)
      CONFIG_NF_NAT: module (pass)
      CONFIG_IP_SET: IP set support: module (pass)
        CONFIG_IP_SET_HASH_IP: hash:ip set support: module (pass)
        CONFIG_IP_SET_HASH_NET: hash:net set support: module (pass)
      CONFIG_IP_VS: IP virtual server support: module (pass)
        CONFIG_IP_VS_NFCT: Netfilter connection tracking: built-in (pass)
        CONFIG_IP_VS_SH: Source hashing scheduling: module (pass)
        CONFIG_IP_VS_RR: Round-robin scheduling: module (pass)
        CONFIG_IP_VS_WRR: Weighted round-robin scheduling: module (pass)
      CONFIG_NF_CONNTRACK_IPV4: IPv4 connetion tracking support (required for NAT): unknown (warning)
      CONFIG_NF_REJECT_IPV4: IPv4 packet rejection: module (pass)
      CONFIG_NF_NAT_IPV4: IPv4 NAT: unknown (warning)
      CONFIG_IP_NF_IPTABLES: IP tables support: module (pass)
        CONFIG_IP_NF_FILTER: Packet filtering: module (pass)
          CONFIG_IP_NF_TARGET_REJECT: REJECT target support: module (pass)
        CONFIG_IP_NF_NAT: iptables NAT support: module (pass)
        CONFIG_IP_NF_MANGLE: Packet mangling: module (pass)
      CONFIG_NF_DEFRAG_IPV4: module (pass)
      CONFIG_NF_CONNTRACK_IPV6: IPv6 connetion tracking support (required for NAT): unknown (warning)
      CONFIG_NF_NAT_IPV6: IPv6 NAT: unknown (warning)
      CONFIG_IP6_NF_IPTABLES: IP6 tables support: module (pass)
        CONFIG_IP6_NF_FILTER: Packet filtering: module (pass)
        CONFIG_IP6_NF_MANGLE: Packet mangling: module (pass)
        CONFIG_IP6_NF_NAT: ip6tables NAT support: module (pass)
      CONFIG_NF_DEFRAG_IPV6: module (pass)
    CONFIG_BRIDGE: 802.1d Ethernet Bridging: module (pass)
      CONFIG_LLC: module (pass)
      CONFIG_STP: module (pass)
  CONFIG_EXT4_FS: The Extended 4 (ext4) filesystem: built-in (pass)
  CONFIG_PROC_FS: /proc file system support: built-in (pass)

What happened?

ControlNode lists controllers that were removed from cluster using either k0s etcd leave (and follow-up commands from https://docs.k0sproject.io/v1.28.4+k0s.0/remove_controller/) or k0sctl run with reset flag and then removal from YAML

Moreover ControlNode has limited usability with current fields. Only IP and hostname are available.

Steps to reproduce

1. Install cluster
2. Follow https://docs.k0sproject.io/v1.28.4+k0s.0/remove_controller/ or apply changes with k0sctl - reset and then remove
3. Check k0s kubectl get ControlNode

Expected behavior

Removed node is not there. Data about controllers is more useful.

Actual behavior

• Removed node still shows up, even if k0s etcd member-list doesn't show it.
• k0s kubectl get ControlNode shows only creation date, hostname and IP address

Screenshots and logs

No response

Additional context

See k0sproject/k0sctl#603 (comment) for context and some logs.

[twz123]

ControlNode lists controllers that were removed from cluster

Right. Node removal is generally not automated in the k0s ecosystem, currently. Thanks for pointing out the missing docs about this (#3809).

Moreover ControlNode has limited usability with current fields.

This custom resource is merely an implementation detail of the k0s autopilot functionality, and is therefore limited to supporting what is required to implement automatic upgrades in k0s.

[danielskowronski]

This custom resource is merely an implementation detail of the k0s autopilot functionality, and is therefore limited to supporting what is required to implement automatic upgrades in k0s.

Is it something we could extend? As far as I've checked, this seems to be the only API available for operators to query cluster status, and it'd be reasonable for some aspects to be reachable within k8s APIs.

[github-actions]

The issue is marked as stale since no activity has been recorded in 30 days

[jnummelin]

Is it something we could extend?

I think we should rather design custom resources dedicated for these purposes, otherwise we make the autopilot related ones like swiss army knives. :)

We have some working ideas, need to finalize those into a specification form for further discussion and planning.

[github-actions]

The issue is marked as stale since no activity has been recorded in 30 days