kubelet: enabling unsafe sysctls not working

[nitishkumar71]

What Happened?

Based on the doc, I am trying to create a minikube cluster using command minikube start --extra-config="kubelet.allowed-unsafe-sysctls=vm.max_map_count" to enable unsafe sysctl vm.max_map_count. Kubernetes cluster setup initialization is failing in this case, although it works if i just try minikube start

Attach the log file

😄 minikube v1.34.0 on Debian 12.7
✨ Automatically selected the docker driver. Other choices: qemu2, ssh
📌 Using rootless Docker driver
👍 Starting "minikube" primary control-plane node in "minikube" cluster
🚜 Pulling base image v0.0.45 ...
🔥 Creating docker container (CPUs=2, Memory=7400MB) ...
🐳 Preparing Kubernetes v1.31.0 on Docker 27.2.0 ...
▪ kubelet.allowed-unsafe-sysctls=vm.max_map_count
▪ Generating certificates and keys ...
▪ Booting up control plane ...
💢 initialization failed, will try again: wait: /bin/bash -c "sudo env PATH="/var/lib/minikube/binaries/v1.31.0:$PATH" kubeadm init --config /var/tmp/minikube/kubeadm.yaml --ignore-preflight-errors=DirAvailable--etc-kubernetes-manifests,DirAvailable--var-lib-minikube,DirAvailable--var-lib-minikube-etcd,FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml,FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml,FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml,FileAvailable--etc-kubernetes-manifests-etcd.yaml,Port-10250,Swap,NumCPU,Mem,SystemVerification,FileContent--proc-sys-net-bridge-bridge-nf-call-iptables": Process exited with status 1
stdout:
[init] Using Kubernetes version: v1.31.0
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
KERNEL_VERSION: 6.1.0-28-amd64
OS: Linux
CGROUPS_CPU: enabled
CGROUPS_CPUSET: missing
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
CGROUPS_PIDS: enabled
CGROUPS_HUGETLB: missing
CGROUPS_IO: missing
[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 beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/var/lib/minikube/certs"
[certs] Using existing ca certificate authority
[certs] Using existing apiserver certificate and key on disk
[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 minikube] and IPs [192.168.49.2 127.0.0.1 ::1]
[certs] Generating "etcd/peer" certificate and key
[certs] etcd/peer serving cert is signed for DNS names [localhost minikube] and IPs [192.168.49.2 127.0.0.1 ::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 "super-admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[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"
[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
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests"
[kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s
[kubelet-check] The kubelet is not healthy after 4m0.000303213s

Unfortunately, an error has occurred:
The HTTP call equal to 'curl -sSL http://127.0.0.1:10248/healthz' returned error: Get "http://127.0.0.1:10248/healthz": context deadline exceeded

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/cri-dockerd.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/cri-dockerd.sock logs CONTAINERID'

stderr:
W1216 16:13:40.231803 1840 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "ClusterConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
W1216 16:13:40.232798 1840 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "InitConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
[WARNING Swap]: swap is supported for cgroup v2 only. The kubelet must be properly configured to use swap. Please refer to https://kubernetes.io/docs/concepts/architecture/nodes/#swap-memory, or disable swap on the node
[WARNING SystemVerification]: missing optional cgroups: hugetlb io
[WARNING SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "modprobe: FATAL: Module configs not found in directory /lib/modules/6.1.0-28-amd64\n", err: exit status 1
[WARNING SystemVerification]: missing required cgroups: cpuset
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase wait-control-plane: could not initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher

▪ Generating certificates and keys ...
▪ Booting up control plane ...

💣 Error starting cluster: wait: /bin/bash -c "sudo env PATH="/var/lib/minikube/binaries/v1.31.0:$PATH" kubeadm init --config /var/tmp/minikube/kubeadm.yaml --ignore-preflight-errors=DirAvailable--etc-kubernetes-manifests,DirAvailable--var-lib-minikube,DirAvailable--var-lib-minikube-etcd,FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml,FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml,FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml,FileAvailable--etc-kubernetes-manifests-etcd.yaml,Port-10250,Swap,NumCPU,Mem,SystemVerification,FileContent--proc-sys-net-bridge-bridge-nf-call-iptables": Process exited with status 1
stdout:
[init] Using Kubernetes version: v1.31.0
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
KERNEL_VERSION: 6.1.0-28-amd64
OS: Linux
CGROUPS_CPU: enabled
CGROUPS_CPUSET: missing
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
CGROUPS_PIDS: enabled
CGROUPS_HUGETLB: missing
CGROUPS_IO: missing
[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 beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/var/lib/minikube/certs"
[certs] Using existing ca certificate authority
[certs] Using existing apiserver certificate and key on disk
[certs] Using existing apiserver-kubelet-client certificate and key on disk
[certs] Using existing front-proxy-ca certificate authority
[certs] Using existing front-proxy-client certificate and key on disk
[certs] Using existing etcd/ca certificate authority
[certs] Using existing etcd/server certificate and key on disk
[certs] Using existing etcd/peer certificate and key on disk
[certs] Using existing etcd/healthcheck-client certificate and key on disk
[certs] Using existing apiserver-etcd-client certificate and key on disk
[certs] Using the existing "sa" key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "super-admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[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"
[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
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests"
[kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s
[kubelet-check] The kubelet is not healthy after 4m0.001195671s

Unfortunately, an error has occurred:
The HTTP call equal to 'curl -sSL http://127.0.0.1:10248/healthz' returned error: Get "http://127.0.0.1:10248/healthz": context deadline exceeded

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/cri-dockerd.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/cri-dockerd.sock logs CONTAINERID'

stderr:
W1216 16:17:43.098039 5581 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "ClusterConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
W1216 16:17:43.098713 5581 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "InitConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
[WARNING Swap]: swap is supported for cgroup v2 only. The kubelet must be properly configured to use swap. Please refer to https://kubernetes.io/docs/concepts/architecture/nodes/#swap-memory, or disable swap on the node
[WARNING SystemVerification]: missing optional cgroups: hugetlb io
[WARNING SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "modprobe: FATAL: Module configs not found in directory /lib/modules/6.1.0-28-amd64\n", err: exit status 1
[WARNING SystemVerification]: missing required cgroups: cpuset
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase wait-control-plane: could not initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher

╭───────────────────────────────────────────────────────────────────────────────────────────╮
│ │
│ 😿 If the above advice does not help, please let us know: │
│ 👉 https://github.com/kubernetes/minikube/issues/new/choose │
│ │
│ Please run minikube logs --file=logs.txt and attach logs.txt to the GitHub issue. │
│ │
╰───────────────────────────────────────────────────────────────────────────────────────────╯

❌ Exiting due to K8S_KUBELET_NOT_RUNNING: wait: /bin/bash -c "sudo env PATH="/var/lib/minikube/binaries/v1.31.0:$PATH" kubeadm init --config /var/tmp/minikube/kubeadm.yaml --ignore-preflight-errors=DirAvailable--etc-kubernetes-manifests,DirAvailable--var-lib-minikube,DirAvailable--var-lib-minikube-etcd,FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml,FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml,FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml,FileAvailable--etc-kubernetes-manifests-etcd.yaml,Port-10250,Swap,NumCPU,Mem,SystemVerification,FileContent--proc-sys-net-bridge-bridge-nf-call-iptables": Process exited with status 1
stdout:
[init] Using Kubernetes version: v1.31.0
[preflight] Running pre-flight checks
[preflight] The system verification failed. Printing the output from the verification:
KERNEL_VERSION: 6.1.0-28-amd64
OS: Linux
CGROUPS_CPU: enabled
CGROUPS_CPUSET: missing
CGROUPS_DEVICES: enabled
CGROUPS_FREEZER: enabled
CGROUPS_MEMORY: enabled
CGROUPS_PIDS: enabled
CGROUPS_HUGETLB: missing
CGROUPS_IO: missing
[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 beforehand using 'kubeadm config images pull'
[certs] Using certificateDir folder "/var/lib/minikube/certs"
[certs] Using existing ca certificate authority
[certs] Using existing apiserver certificate and key on disk
[certs] Using existing apiserver-kubelet-client certificate and key on disk
[certs] Using existing front-proxy-ca certificate authority
[certs] Using existing front-proxy-client certificate and key on disk
[certs] Using existing etcd/ca certificate authority
[certs] Using existing etcd/server certificate and key on disk
[certs] Using existing etcd/peer certificate and key on disk
[certs] Using existing etcd/healthcheck-client certificate and key on disk
[certs] Using existing apiserver-etcd-client certificate and key on disk
[certs] Using the existing "sa" key
[kubeconfig] Using kubeconfig folder "/etc/kubernetes"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "super-admin.conf" kubeconfig file
[kubeconfig] Writing "kubelet.conf" kubeconfig file
[kubeconfig] Writing "controller-manager.conf" kubeconfig file
[kubeconfig] Writing "scheduler.conf" kubeconfig file
[etcd] Creating static Pod manifest for local etcd in "/etc/kubernetes/manifests"
[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"
[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
[wait-control-plane] Waiting for the kubelet to boot up the control plane as static Pods from directory "/etc/kubernetes/manifests"
[kubelet-check] Waiting for a healthy kubelet at http://127.0.0.1:10248/healthz. This can take up to 4m0s
[kubelet-check] The kubelet is not healthy after 4m0.001195671s

Unfortunately, an error has occurred:
The HTTP call equal to 'curl -sSL http://127.0.0.1:10248/healthz' returned error: Get "http://127.0.0.1:10248/healthz": context deadline exceeded

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/cri-dockerd.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/cri-dockerd.sock logs CONTAINERID'

stderr:
W1216 16:17:43.098039 5581 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "ClusterConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
W1216 16:17:43.098713 5581 common.go:101] your configuration file uses a deprecated API spec: "kubeadm.k8s.io/v1beta3" (kind: "InitConfiguration"). Please use 'kubeadm config migrate --old-config old.yaml --new-config new.yaml', which will write the new, similar spec using a newer API version.
[WARNING Swap]: swap is supported for cgroup v2 only. The kubelet must be properly configured to use swap. Please refer to https://kubernetes.io/docs/concepts/architecture/nodes/#swap-memory, or disable swap on the node
[WARNING SystemVerification]: missing optional cgroups: hugetlb io
[WARNING SystemVerification]: failed to parse kernel config: unable to load kernel module: "configs", output: "modprobe: FATAL: Module configs not found in directory /lib/modules/6.1.0-28-amd64\n", err: exit status 1
[WARNING SystemVerification]: missing required cgroups: cpuset
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase wait-control-plane: could not initialize a Kubernetes cluster
To see the stack trace of this error execute with --v=5 or higher

💡 Suggestion: Check output of 'journalctl -xeu kubelet', try passing --extra-config=kubelet.cgroup-driver=systemd to minikube start
🍿 Related issue: #4172

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