Add conntrack to ISO - required for Kubernetes v1.18.x

[tstromberg]

We should aim to update the LatestVersion constant to a v1.18 alpha in the v1.8.0 release so that there is time for us to battle-test Kubernetes v1.18 in minikube before the big release date.

Assuming #6603 is merged, minikube fails here with v1.18.0-alpha5.

213 11:57:11.300721   68618 exit.go:101] Error starting cluster: init failed. output: "-- stdout --\n[init] Using Kubernetes version: v1.18.0-alpha.5\n[preflight] Running pre-flight checks\n\n-- /stdout --\n** stderr ** \nW0213 19:57:08.866611    2776 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]\n\t[WARNING IsDockerSystemdCheck]: detected \"cgroupfs\" as the Docker cgroup driver. The recommended driver is \"systemd\". Please follow the guide at https://kubernetes.io/docs/setup/cri/\n\t[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'\nerror execution phase preflight: [preflight] Some fatal errors occurred:\n\t[ERROR FileExisting-conntrack]: conntrack not found in system path\n[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`\nTo see the stack trace of this error execute with --v=5 or higher\n\n** /stderr **": /bin/bash -c "sudo env PATH=/var/lib/minikube/binaries/v1.18.0-alpha.5:$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,SystemVerification": Process exited with status 1
stdout:
[init] Using Kubernetes version: v1.18.0-alpha.5
[preflight] Running pre-flight checks

stderr:
W0213 19:57:08.866611    2776 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
	[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
	[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase preflight: [preflight] Some fatal errors occurred:
	[ERROR FileExisting-conntrack]: conntrack not found in system path
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

💣  Error starting cluster: init failed. output: "-- stdout --\n[init] Using Kubernetes version: v1.18.0-alpha.5\n[preflight] Running pre-flight checks\n\n-- /stdout --\n** stderr ** \nW0213 19:57:08.866611    2776 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]\n\t[WARNING IsDockerSystemdCheck]: detected \"cgroupfs\" as the Docker cgroup driver. The recommended driver is \"systemd\". Please follow the guide at https://kubernetes.io/docs/setup/cri/\n\t[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'\nerror execution phase preflight: [preflight] Some fatal errors occurred:\n\t[ERROR FileExisting-conntrack]: conntrack not found in system path\n[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`\nTo see the stack trace of this error execute with --v=5 or higher\n\n** /stderr **": /bin/bash -c "sudo env PATH=/var/lib/minikube/binaries/v1.18.0-alpha.5:$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,SystemVerification": Process exited with status 1
stdout:
[init] Using Kubernetes version: v1.18.0-alpha.5
[preflight] Running pre-flight checks

stderr:
W0213 19:57:08.866611    2776 configset.go:202] WARNING: kubeadm cannot validate component configs for API groups [kubelet.config.k8s.io kubeproxy.config.k8s.io]
	[WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/
	[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
error execution phase preflight: [preflight] Some fatal errors occurred:
	[ERROR FileExisting-conntrack]: conntrack not found in system path
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

[tstromberg]

It's worth noting that Kubernetes v1.18 works just fine with the Docker driver, likely because the kind node image includes conntrack already.

[afbjorklund]

We have conntrack-tools 1.4.5 available as a package, so that should be doable...

# BR2_PACKAGE_CONNTRACK_TOOLS is not set

[afbjorklund]

Apparently the dependency was added for both deb and rpm packages. How nice...

It would be great if minikube could get more official kubernetes packaging status. 😐

[afbjorklund]

Looks like we also need a kernel module loaded, for this to work properly.

$ sudo modprobe nf_conntrack     
$ sudo sysctl net.netfilter.nf_conntrack_count
net.netfilter.nf_conntrack_count = 0

[afbjorklund]

And another crio binary as well, which I knew about - but forgot.

runtime config: pinns validation: exec: \"pinns\": executable file not found in $PATH

Remembered to remove "pause", but not to add the new "pinns"....

[afbjorklund]

It was the missing binary that was blocking crio.service, and thus our modprobe