My Rancher cluster is setup around 3 weeks. Everything works fine. But there is one problem while installing MetalLB. I found there is no kubeproxy in my cluster. Even there no kube-proxy pod in every node. I could not follow installation guide to setup config map of kube-proxy
For me, it is really strange to have a cluster without kubeproxy
My setup for rancher cluster is below:
Cluster Provider: RKE
Provision and Provision : Use existing nodes and create a cluster using RKE
Network Plugin : canal
Maybe something I misunderstand. I can discover nodeport and ClusterIP in service correctly.
Finally, I find my kibe-proxy. It is process of host not docker container.
In Racher, we should edit cluster.yml to put extra args for kube-proxy. Rather will apply in every node of cluster automatically.
root 3358919 0.1 0.0 749684 42564 ? Ssl 02:16 0:00 kube-proxy --proxy-mode=ipvs --ipvs-scheduler=lc --ipvs-strict-arp=true --cluster-cidr=10.42.0.0/16
Related
Setting up a K8S cluster (RKE) on Hetzner, having 3 Ubuntu 22 worker nodes, using the Hetzner LoadBalancer.
So I tried to run the Google "hello" app and create service and Ingress.
Problem: it only works 1/3 of the time.
Can ingress running on node 1 not use a pod running on node 2 as backend? This would make the Hetzner load balancer unusable for this use case I suppose?
Had to change the network to flannel, then it worked.
I accidentally deleted kube-proxy daemonset by using command: kubectl delete -n kube-system daemonset kube-proxy which should run kube-proxy pods in my cluster, what the best way to restore it?
That's how it should look
Kubernetes allows you to reinstall kube-proxy by running the following command which install the kube-proxy addon components via the API server.
$ kubeadm init phase addon kube-proxy --kubeconfig ~/.kube/config --apiserver-advertise-address string
This will generate the output as
[addons] Applied essential addon: kube-proxy
The IP address the API Server will advertise it's listening on. If not set the default network interface will be used.
Hence kube-proxy will be reinstalled in the cluster by creating a DaemonSet and launching the pods.
kube-proxy daemon got created at the time of cluster creation, so you need to write your own manifest for daemon-set unless you have a backup to restore it from there.
I have the kops cluster running on AWS. I would like to extend the service node port range of that cluster without restart the cluster.
Is it possible? If yes, how can it be done?
You can change it, but it does require a reboot of the control plane nodes (but not the woker nodes). This is due to the "immutable" nature of the kOps configuration.
To change the range, add this to your cluster spec:
spec:
kubeAPIServer:
serviceNodePortRange: <range>
See the cluster spec for more information.
Keep ensure you do not conflict with the ports kOps require
I am trying to setup my very first Kubernetes cluster and it seems to have setup fine until nginx-ingress controller.
Here is my cluster information:
Nodes: three RHEL7 and one RHEL8 nodes
Master is running on RHEL7
Kubernetes server version: 1.19.1
Networking used: flannel
coredns is running fine.
selinux and firewall are disabled on all nodes
Here are my all pods running in kube-system
I then followed instructions on following page to install nginx ingress controller: https://docs.nginx.com/nginx-ingress-controller/installation/installation-with-manifests/
Instead of deployment, I decided to use daemon-set since I am going to have only few nodes running in my kubernetes cluster.
After following the instructions, pod on my RHEL8 is constantly failing with the following error:
Readiness probe failed: Get "http://10.244.3.2:8081/nginx-ready": dial
tcp 10.244.3.2:8081: connect: connection refused Back-off restarting
failed container
Here is the screenshot shows that RHEL7 pods are working just fine and RHEL8 is failing:
All nodes are setup exactly the same way and there is no difference.
I am very new to Kubernetes and don't know much internals of it. Can someone please point me on how can I debug and fix this issue? I am really willing to learn from issues like this.
This is how I provisioned RHEL7 and RHEL8 nodes
Installed docker version: 19.03.12, build 48a66213fe
Disabled firewalld
Disabled swap
Disabled SELinux
To enable iptables to see bridged traffic, set net.bridge.bridge-nf-call-ip6tables = 1 and net.bridge.bridge-nf-call-iptables = 1
Added hosts entry for all the nodes involved in Kubernetes cluster so that they can find each other without hitting DNS
Added IP address of all nodes in Kubernetes cluster on /etc/environment for no_proxy so that it doesn't hit corporate proxy
Verified docker driver to be "systemd" and NOT "cgroupfs"
Reboot server
Install kubectl, kubeadm, kubelet as per kubernetes guide here at: https://kubernetes.io/docs/tasks/tools/install-kubectl/
Start and enable kubelet service
Initialize master by executing the following:
kubeadm init --pod-network-cidr=10.244.0.0/16 --service-cidr=10.96.0.0/12
Apply node-selector patch for mixed OS scheduling
wget https://raw.githubusercontent.com/Microsoft/SDN/master/Kubernetes/flannel/l2bridge/manifests/node-selector-patch.yml
kubectl patch ds/kube-proxy --patch "$(cat node-selector-patch.yml)" -n=kube-system
Apply flannel CNI
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
Modify net-conf.json section of kube-flannel.yml for a type "host-gw"
kubectl apply -f kube-flannel.yml
Apply node selector patch
kubectl patch ds/kube-flannel-ds-amd64 --patch "$(cat node-selector-patch.yml)" -n=kube-system
Thanks
According to kubernetes documentation the list of supported host operating systems is as follows:
Ubuntu 16.04+
Debian 9+
CentOS 7
Red Hat Enterprise Linux (RHEL) 7
Fedora 25+
HypriotOS v1.0.1+
Flatcar Container Linux (tested with 2512.3.0)
This article mentioned that there are network issues on RHEL 8:
(2020/02/11 Update: After installation, I keep facing pod network issue which is like deployed pod is unable to reach external network
or pods deployed in different workers are unable to ping each other
even I can see all nodes (master, worker1 and worker2) are ready via
kubectl get nodes. After checking through the Kubernetes.io official website, I observed the nfstables backend is not compatible with the
current kubeadm packages. Please refer the following link in “Ensure
iptables tooling does not use the nfstables backend”.
The simplest solution here is to reinstall the node on supported operating system.
Use Rancher server on several servers:
Master
Node1
Node2
Node3
Maybe only need rancher agent on node servers.
Also want to make kubernetes cluster on these servers. So install Kubernetes master on Rancher master, install Kubernetes nodes(kubelet) on Rancher nodes. Is it right?
So, the Kubernetes nodes can't install using Rancher server but should do it by self?
You will need a Rancher Agent on any server you want Rancher to place containers on. Rancher can deploy Kubernetes for you. I believe what you want to do is add all of the nodes, including the Rancher master, to a single Cattle environment(The Default env is Cattle). When adding the Rancher Server make sure you set CATTLE_AGENT_IP=. Once the hosts are registered, you will want to set host labels on the nodes. For nodes 1,2,3 you will set the label compute=true. On the Rancher Server you will set host 2 host labels, etcd=true and orchestration=true.
Once the labels are set up. Click on Catalog and search for Kubernetes. You can probably stick with most defaults, but CHANGE plane isolation to required.
Rancher should deploy Kubernetes management servers on the same host as your Rancher Server and the remaining nodes will be Kuberenetes minions.