I have make my deployment work with istio ingressgateway before. I am not aware of any changes made in istio or k8s side.
When I tried to deploy, I see an error in replicaset side that's why it cannot create new pod.
Error creating: Internal error occurred: failed calling webhook
"namespace.sidecar-injector.istio.io": Post
"https://istiod.istio-system.svc:443/inject?timeout=10s": dial tcp
10.104.136.116:443: connect: no route to host
When I try to go inside api-server and ping 10.104.136.116 (istiod service IP) it just hangs.
What I have tried so far:
Deleted all coredns pods
Deleted all istiod pods
Deleted all weave pods
Reinstalling istio via istioctl x uninstall --purge
turning all of VMs firewall
sudo iptables -P INPUT ACCEPT
sudo iptables -P FORWARD ACCEPT
sudo iptables -P OUTPUT ACCEPT
sudo iptables -F
restarted all of the nodes
manual istio pod injection
Setup
k8s version: 1.21.2
istio: 1.10.3
HA setup
CNI: weave
CRI: containerd
In my case this was related to firewall. More info can be found here.
The gist of it is that on GKE at least you need to open another port 15017 in addition to 10250 and 443. This is to allow communication from your master node(s) to you VPC.
I don't have a definite answer unto why is this happening. But kube-apiserver cannot access istiod via service IP, wherein it can connect when I used the istiod pod IP.
Since I don't have the control over the VM and lower networking layer and not sure if they have changed something (because it is working before).
I made this work by changing my CNI from weave to flannel
In my case it was due to firewall. Following this Istio debug guide, I identified that the kubectl get --raw /api/v1/namespaces/istio-system/services/https:istiod:https-webhook/proxy/inject -v4 command was timing out while all other cluster internal calls were ok.
The best way to diagnose this is to open temporarly your AWS Security Groups involved to 0.0.0.0/0 for port 15017 and then try again.
If the errror won't show again, you know there's need to fix this part.
I am using EKS with Amazon VPC CNI v1.12.2-eksbuild.1
Related
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.
I am working on setting up istio in my kubernetes cluster.
I downloaded istio-1.4.2 and installed demo profile and did manual sidecar injection.
But when I check sidecar pod logs, I am getting the below error.
2019-12-26T08:54:17.694727Z error k8s.io/client-go#v11.0.1-0.20190409021438-1a26190bd76a+incompatible/tools/cache/reflector.go:98: Failed to list *v1beta1.MutatingWebhookConfiguration: Get https://10.96.0.1:443/apis/admissionregistration.k8s.io/v1beta1/mutatingwebhookconfigurations?fieldSelector=metadata.name%3Distio-sidecar-injector&limit=500&resourceVersion=0: dial tcp 10.96.0.1:443: connect: connection refused
It seems to be the networking issue, but could you please let me know what it is trying to do exactly?
Is there a way to get more logs than just 'connection refused'?
How do we verify networking issues between istio pods. It seems I cannot run 'wget', 'curl', 'tcpdump', 'netstat' etc within istio sidecar pod to debug further.
All the pods in kube-system namespace are working fine.
Check what port your API Server is serving https traffic(controlled by this flag --secure-port int Default: 6443). It may be 6443 instead of 443.
Check what is the value of server in your kubeconfig and are you able to connect to your kubernetes via kubectl using that kubeconfig.
Another thing to check is whether you have network policy attached to the namespace which blocks egress traffic.
And you could use an ephemeral container to debug issue with the sidecar
https://kubernetes.io/docs/concepts/workloads/pods/ephemeral-containers/
https://github.com/aylei/kubectl-debug
the kube-apiserver isn't running
/var/log/kube-apiserver.log has the following:
Flag --address has been deprecated, see --insecure-bind-address instead.
Where are these values stored / configured?
I mean yes the originate from my kops config, which I've now modified. But I'm not able to get these changes reflected:
kops rolling-update cluster
Using cluster from kubectl context: uuuuuuuuuuuuuuuuuuuuuu
Unable to reach the kubernetes API.
Use --cloudonly to do a rolling-update without confirming progress with the k8s API
error listing nodes in cluster: Get https://api.uuuuuuuuuu/api/v1/nodes: dial tcp eeeeeeeeeeeeeee:443: connect: connection refused
https://stackoverflow.com/a/50356764/1663462
Modify /etc/kubernetes/manifests/kube-apiserver.manifest
And then restart kubelet: systemctl restart kubelet
I'm trying to deploy Kubernetes with Calico (IPIP) with Kubeadm. After deployment is done I'm deploying Calico using these manifests
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml
Before applying it, I'm editing CALICO_IPV4POOL_CIDR and setting it to 10.250.0.0/17 as well as using command kubeadm init --pod-cidr 10.250.0.0/17.
After few seconds CoreDNS pods (for example getting addr 10.250.2.2) starts restarting with error 10.250.2.2:8080 connection refused.
Now a bit of digging:
from any node in cluster ping 10.250.2.2 works and it reaches pod (tcpdump in pod net namespace shows it).
from different pod (on different node) curl 10.250.2.2:8080 works well
from any node to curl 10.250.2.2:8080 fails with connection refused
Because it's coredns pod it listens on 53 both udp and tcp, so I've tried netcat from nodes
nc 10.250.2.2 53 - connection refused
nc -u 10.250.2.2 55 - works
Now I've tcpdump each interface on source node for port 8080 and curl to CoreDNS pod doesn't even seem to leave node... sooo iptables?
I've also tried weave, canal and flannel, all seem to have same issue.
I've ran out of ideas by now...any pointers please?
Seems to be a problem with Calico implementation, CoreDNS Pods are sensitive on the CNI network Pods successful functioning.
For proper CNI network plugin implementation you have to include --pod-network-cidr flag to kubeadm init command and afterwards apply the same value to CALICO_IPV4POOL_CIDR parameter inside calico.yml.
Moreover, for a successful Pod network installation you have to apply some RBAC rules in order to make sufficient permissions in compliance with general cluster security restrictions, as described in official Kubernetes documentation:
For Calico to work correctly, you need to pass
--pod-network-cidr=192.168.0.0/16 to kubeadm init or update the calico.yml file to match your Pod network. Note that Calico works on
amd64 only.
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/rbac-kdd.yaml
kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/installation/hosted/kubernetes-datastore/calico-networking/1.7/calico.yaml
In your case I would switched to the latest Calico versions at least from v3.3 as given in the example.
If you've noticed that you run Pod network plugin installation properly, please take a chance and update the question with your current environment setup and Kubernetes components versions with a health statuses.
Version: kubeadm and kubectl 1.12
I get this error when I change the hostname of one of the Kubernetes slaves.
The error I get from the metric service:
dial tcp: lookup ops-kube-slave-dev-1 on 10.96.0.10:53: no such host
This IP is not the public or private IP and is completely random.
I add this to the file /etc/hosts:
10.0.1.248 ops-kube-slave-dev-2
10.0.1.154 ops-kube-slave-dev-1
When I execute $ nslookup ops-kube-slave-dev-2, I get the correct IP.
But still the same error. I want to avoid that for every new node I add to create a new certificate again.
What is the best solution for auto join slave node?
The solution is to provide --hostname-override option to the kubelet configuration (in my case, /etc/systemd/system/kubelet.service.d/10-kubeadm.conf). Let you allow to change the kubernetes nodename without regenerating the certificates.
For more info, see https://prefetch.net/blog/2017/12/30/getting-your-kubernetes-node-names-right/.
PS: On the secondary note,The IP you're talking about is not random, that is the IP of kubedns service of your cluster. You can check it using $ kubectl get svc -n kube-system.
Hope this helps.