kubernetes dashboard reachable with curl but not chrome/firefox via kubectl proxy - google-chrome

I have two clusters that are very different (one kubernetes 1.13 with dashboard 1.0 and created with kops in aws; the other uses kubernetes 1.14 with dashboard 2.0 and created with EKS) same issue for both, and I use kubectl 1.17 to interface with both. Once I start kubectl proxy, I can reach the dashboard I just installed via curl. Eg with the dashboard 2.0 in newer EKS cluster:
In one terminal:
$ kubectl proxy
Starting to serve on 127.0.0.1:8001
In another terminal
$ curl http://127.0.0.1:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/
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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Kubernetes Dashboard</title>
<link rel="icon" type="image/png" href="assets/images/kubernetes-logo.png"/>
<meta name="viewport" content="width=device-width">
<link rel="stylesheet" href="styles.d8a1833bf9631b49f8ae.css"></head>
<body>
<kd-root></kd-root>
<script src="runtime.a3c2fb5c390e8fb10577.js" defer=""></script><script src="polyfills-es5.ddf623b9f96429e29863.js" nomodule="" defer=""></script><script src="polyfills.24a7a4821c30c3b30717.js" defer=""></script><script src="scripts.391d299173602e261418.js" defer=""></script><script src="main.a0d83b15387cfc420c65.js" defer=""></script></body>
</html>
Clearly the dashboard service is reachable and responding to the request. The html is a bit different for the other cluster/dashboard combo but still no error.
However the exact same URL from chrome or firefox (running on the same host of course) gives me an error:
This site can’t be reached
127.0.0.1 refused to connect.
Try:
Checking the connection
Checking the proxy and the firewall
ERR_CONNECTION_REFUSED
The dashboard 2.0 itself seems happy:
$ kubectl get all -n kubernetes-dashboard
NAME READY STATUS RESTARTS AGE
pod/dashboard-metrics-scraper-76679bc5b9-k7qjp 1/1 Running 0 136m
pod/kubernetes-dashboard-565688d4c4-dtw5w 1/1 Running 0 136m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/dashboard-metrics-scraper ClusterIP 172.20.42.193 <none> 8000/TCP 142m
service/kubernetes-dashboard ClusterIP 172.20.232.104 <none> 443/TCP 142m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/dashboard-metrics-scraper 1/1 1 1 142m
deployment.apps/kubernetes-dashboard 1/1 1 1 142m
NAME DESIRED CURRENT READY AGE
replicaset.apps/dashboard-metrics-scraper-6c554969c6 0 0 0 137m
replicaset.apps/dashboard-metrics-scraper-76679bc5b9 1 1 1 142m
replicaset.apps/kubernetes-dashboard-565688d4c4 1 1 1 142m
replicaset.apps/kubernetes-dashboard-56c5f95c6b 0 0 0 137m
Any ideas what is wrong? How is it possible that it works with curl and not a web browser?
Updated info:
I checked ifconfig:
$ ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.17.0.2 netmask 255.255.0.0 broadcast 172.17.255.255
...
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
...
With the following kubectl proxy command, I can access dashboard in browser too:
In one terminal:
kubectl proxy --address='172.17.0.2' --accept-hosts='.*'
Then chrome browser to http://172.17.0.2:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/ shows the login screen.
Both flags are necessary otherwise neither curl nor browser will work (the response is Forbidden if I don't use the --accept-hosts -- although that response is from the service so it is at least better than when using loopback).
Replacing by 127.0.0.1 by localhost does not help. I can reach the api server only if I used the full proxy command and http://172.17.0.2:8001/api.
Does anyone know why chrome will not handle 127.0.0.1, whereas curl does, and why this accept-hosts is necessary when curling 172.12 IP but not when using 127 IP?

Well this is embarrassing but I figure I might as well leave this question and post an answer just in case someone else forgets the obvious:
I was shelled into a docker container running on my host when running the curl and kubectl proxy commands (I forgot! as it runs non-stop). The container shares the host's network which is why the 172.17 worked from the browser, but not the loopback.
If you setup the container to port-forward say port 8080 to 8080 (docker ... -p 8080:8080 ...) then the following proxy command (from inside that container) also works:
$ kubectl proxy --port 8080 --address='0.0.0.0'
ie browsing to http://localhost:8080/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/#/login on host works.
Sorry for the mistake!

Related

Unable to connect worker node to master using K3S

I am trying to setup a K3S cluster for learning purposes but I am having trouble connecting the master node with agents. I have looked several tutorials and discussions on this but I can't find a solution. I know I am probably missing something obvious (due to my lack of knowledge), but still help would be much appreciated.
I am using two AWS t2.micro instances with default configuration.
When ssh into the master and installed K3S using
curl -sfL https://get.k3s.io | sh -s - --no-deploy traefik --write-kubeconfig-mode 644 --node-name k3s-master-01
with kubectl get nodes, I am able to see the master
NAME STATUS ROLES AGE VERSION
k3s-master-01 Ready control-plane,master 13s v1.23.6+k3s1
So far it seems I am doing things right. From what I understand, I am supposed to configure the kubeconfig file. So, I accessed it by using
cat /etc/rancher/k3s/k3s.yaml
I copied the configuration file and the server info to match the private IP I took from AWS console, resulting in something like this
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: <lots_of_info>
server: https://<master_private_IP>:6443
name: default
contexts:
- context:
cluster: default
user: default
name: default
current-context: default
kind: Config
preferences: {}
users:
- name: default
user:
client-certificate-data: <my_certificate_data>
client-key-data: <my_key_data>
Then, I ran vi ~/.kube/config, and there I pasted the kubeconfig file
Finally, I grabbed the token with cat /var/lib/rancher/k3s/server/node-token, ssh into the other machine and then run the following
curl -sfL https://get.k3s.io | K3S_NODE_NAME=k3s-worker-01 K3S_URL=https://<master_private_IP>:6443 K3S_TOKEN=<master_token> sh -
The output is
[INFO] Finding release for channel stable
[INFO] Using v1.23.6+k3s1 as release
[INFO] Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.23.6+k3s1/sha256sum-amd64.txt
[INFO] Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.23.6+k3s1/k3s
[INFO] Verifying binary download
[INFO] Installing k3s to /usr/local/bin/k3s
[INFO] Skipping installation of SELinux RPM
[INFO] Creating /usr/local/bin/kubectl symlink to k3s
[INFO] Creating /usr/local/bin/crictl symlink to k3s
[INFO] Creating /usr/local/bin/ctr symlink to k3s
[INFO] Creating killall script /usr/local/bin/k3s-killall.sh
[INFO] Creating uninstall script /usr/local/bin/k3s-agent-uninstall.sh
[INFO] env: Creating environment file /etc/systemd/system/k3s-agent.service.env
[INFO] systemd: Creating service file /etc/systemd/system/k3s-agent.service
[INFO] systemd: Enabling k3s-agent unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s-agent.service → /etc/systemd/system/k3s-agent.service.
[INFO] systemd: Starting k3s-agent
By this output, it looks like I have created an agent. However, when I run kubectl get nodes in the master, I still get
NAME STATUS ROLES AGE VERSION
k3s-master-01 Ready control-plane,master 12m v1.23.6+k3s1
What is the thing I was supposed to do in order to get the agent connected to the master? I am guess I am probably missing something simple, but I just can't seem to find the solution. I've read all the documentation but it is still not clear to me where I am making the mistake. I've tried saving the private master IP and token into the agent as environmental variables with export K3S_TOKEN=master_token and K3S_URL=master_private_IP and then simply running curl -sfL https://get.k3s.io | sh - but I still can't see the worker nodes when running kubectl get nodes
Any help would be appreciated.
It might be your VM instance firewall that prevents appropriate connection from your master to the worker node (and vice versa). Official rancher documentation advise to disable firewall for (Red Hat/CentOS) Enterprise Linux:
It is recommended to turn off firewalld:
systemctl disable firewalld --now
If enabled, it is required to disable nm-cloud-setup and reboot the node:
systemctl disable nm-cloud-setup.service nm-cloud-setup.timer reboot
If you are using Ubuntu on your VM's, there is a different firewall tool (ufw).
In my case, allowing 6443 and 443(not sure if required) port TCP connections worked fine.
Allow port 6443 and TCP connection in all of your cluster machines:
sudo ufw allow 6443/tcp
Then apply k3s installation script in your worker node(s):
curl -sfL https://get.k3s.io | K3S_NODE_NAME=k3s-worker-1 K3S_URL=https://<k3s-master-1 IP>:6443 K3S_TOKEN=<k3s-master-1 TOKEN> sh -
This should work. If not, you can try adding additional allow rule for 443 tcp port as well.
A few options to check.
Check Journalctl for errors
journalctl -u k3s-agent.service -n 300 -xn
If using RaspberryPi for a worker node, make sure you have
cgroup_enable=cpuset cgroup_enable=memory cgroup_memory=1
as the very end of your /boot/cmdline.txt file. DO NOT PUT THIS VALUE ON A NEW LINE! Should just be appended to the end of the line.
If your master node(s) have self-signed certs, make sure you copy the master node's self signed cert to your worker node(s). In linux or raspberry pi copy cert to /usr/local/share/ca-certificates, then issue an
sudo update-ca-certificates
on the worker node
Don't forget to reboot the worker node after you make these changes!
Hope this helps someone!

Istio ingress gateway, getting 403 forbidden error

I am trying to follow the istio gateway and Virtual Service guide at - https://istio.io/docs/tasks/traffic-management/ingress/ingress-control/#determining-the-ingress-ip-and-ports
I can see that these resources (Gateway & VS) are created from Kiali and also from command line. When I try to access my endpoint at curl -I -HHost:httpbin.example.com http://$INGRESS_HOST:$INGRESS_PORT/status/200 I get a 403 Forbidden error.
I am looking at the istio-proxy logs at
k logs httpbin-pod -c istio-proxy -n my-bookinfo
and dont see much there. I am trying to figure out where I can start to debug the issue. Any ideas? (edited)
I guess the HTTP 403 issue might be connected with Istio Authorization or Authentication mesh configurations, assuming that you've successfully injected Envoy sidecar into the particular Pod or widely across related namespaces.
The logs inspection might be most issue explainable task, confirming that Envoy's Access Logs are already enabled, you can look through relevant istio-proxy sidecar and istio-ingressgateway Pod logs; whereas you can fetch Envoy proxy response flags and traffic path workflow:
$ kubectl logs -l app=httpbin -c istio-proxy
[2019-03-06T09:31:27.360Z] "GET /status/418 HTTP/1.1" 418 - "-" 0 135
5 2 "-" "curl/7.60.0" "d209e46f-9ed5-9b61-bbdd-43e22662702a"
"httpbin:8000" "127.0.0.1:80"
inbound|8000|http|httpbin.default.svc.cluster.local - 172.30.146.73:80
172.30.146.82:38618 outbound_.8000_._.httpbin.default.svc.cluster.local
Check Authentication Policies within a mesh, that can affect sidecars proxy behavior and revise a global mesh policy in terms of mTLS authentication, Permissive mode is enabled by default:
$ kubectl get policies.authentication.istio.io --all-namespaces
$ kubectl get meshpolicy.authentication.istio.io default -oyaml
If you launched Authorization rules within a mesh, verify all the corresponded RBAC policies:
$ kubectl get clusterrbacconfigs.rbac.istio.io --all-namespaces
$ kubectl get authorizationpolicies.rbac.istio.io,rbacconfigs.rbac.istio.io,servicerolebindings.rbac.istio.io,serviceroles.rbac.istio.io --all-namespaces
Find more related information about troubleshooting steps in the official Istio documentation.

route to application stopped working in OpenShift Online 3.9

I have an application running in Openshift Online starter, which worked for the last 5 months. A single pod behind a service with a route defined that does edge tls termination.
Since Saturday, when trying to access the application, I get the error message
Application is not available
The application is currently not serving requests at this endpoint. It may not have been started or is still starting.
Possible reasons you are seeing this page:
The host doesn't exist. Make sure the hostname was typed correctly and that a route matching this hostname exists.
The host exists, but doesn't have a matching path. Check if the URL path was typed correctly and that the route was created using the desired path.
Route and path matches, but all pods are down. Make sure that the resources exposed by this route (pods, services, deployment configs, etc) have at least one pod running.
The pod is running, I can exec into it and check this, I can port-forward to it and access it.
checking the different components with oc:
$ oc get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE
taboo3-23-jt8l8 1/1 Running 0 1h 10.128.37.90 ip-172-31-30-113.ca-central-1.compute.internal
$ oc get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
taboo3 172.30.238.44 <none> 8080/TCP 151d
$ oc describe svc taboo3
Name: taboo3
Namespace: sothawo
Labels: app=taboo3
Annotations: openshift.io/generated-by=OpenShiftWebConsole
Selector: deploymentconfig=taboo3
Type: ClusterIP
IP: 172.30.238.44
Port: 8080-tcp 8080/TCP
Endpoints: 10.128.37.90:8080
Session Affinity: None
Events: <none>
$ oc get route
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
taboo3 taboo3-sothawo.193b.starter-ca-central-1.openshiftapps.com taboo3 8080-tcp edge/Redirect None
I tried to add a new route as well (with or without tls), but am getting the same error.
Does anybody have an idea what might be causing this and how to fix it?
Addition April 17, 2018: Got an email from Openshift Online support:
It looks like you may be affected by this bug.
So waiting for it to be resolved.
The problem has been resolved by Openshift Online, the application is working again

go-ethereum - geth - puppeth - ethstat remote server : docker: command not found

I'm trying to setup a private ethereum test network using Puppeth (as Péter Szilágyi demoed in Ethereum devcon three 2017). I'm running it on a macbook pro (macOS Sierra).
When I try to setup the ethstat network component I get an "docker configured incorrectly: bash: docker: command not found" error. I have docker running and I can use it fine in the terminal e.g. docker ps.
Here are the steps I took:
What would you like to do? (default = stats)
1. Show network stats
2. Manage existing genesis
3. Track new remote server
4. Deploy network components
> 4
What would you like to deploy? (recommended order)
1. Ethstats - Network monitoring tool
2. Bootnode - Entry point of the network
3. Sealer - Full node minting new blocks
4. Wallet - Browser wallet for quick sends (todo)
5. Faucet - Crypto faucet to give away funds
6. Dashboard - Website listing above web-services
> 1
Which server do you want to interact with?
1. Connect another server
> 1
Please enter remote server's address:
> localhost
DEBUG[11-15|22:46:49] Attempting to establish SSH connection server=localhost
WARN [11-15|22:46:49] Bad SSH key, falling back to passwords path=/Users/xxx/.ssh/id_rsa err="ssh: cannot decode encrypted private keys"
The authenticity of host 'localhost:22 ([::1]:22)' can't be established.
SSH key fingerprint is xxx [MD5]
Are you sure you want to continue connecting (yes/no)? yes
What's the login password for xxx at localhost:22? (won't be echoed)
>
DEBUG[11-15|22:47:11] Verifying if docker is available server=localhost
ERROR[11-15|22:47:11] Server not ready for puppeth err="docker configured incorrectly: bash: docker: command not found\n"
Here are my questions:
Is there any documentation / tutorial describing how to setup this remote server properly. Or just on puppeth in general?
Can I not use localhost as "remote server address"
Any ideas on why the docker command is not found (it is installed and running and I can use it ok in the terminal).
Here is what I did.
For the docker you have to use the docker-compose binary. You can find it here.
Furthermore, you have to be sure that an ssh server is running on your localhost and that keys have been generated.
I didn't find any documentations for puppeth whatsoever.
I think I found the root cause to this problem. The SSH daemon is compiled with a default path. If you ssh to a machine with a specific command (other than a shell), you get that default path. This does not include /usr/local/bin for example, where docker lives in my case.
I found the solution here: https://serverfault.com/a/585075:
edit /etc/ssh/sshd_config and make sure it contains PermitUserEnvironment yes (you need to edit this with sudo)
create a file ~/.ssh/environment with the path that you want, in my case:
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
When you now run ssh localhost env you should see a PATH that matches whatever you put in ~/.ssh/environment.

Openshift Origin registry: how to make it accessible?

We are setting up a test cloud Openshift Origin which we created using the openshift ansible playbook. We are following the documentation at: https://docs.openshift.com/container-platform/latest/install_config/install/advanced_install.html
We have not done anything special concerning the openshift registry or router.
We are pretty new to this topic and we tried since few tags to bring the openshift registry accessible....
We have 3 hosts:
master (unschedulable)
node-1 which is set to the region 'infra' and has the registry and router services
node-2 (other region).
Here the services running on the default project:
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
docker-registry 172.30.78.66 <none> 5000/TCP 3h
kubernetes 172.30.0.1 <none> 443/TCP,53/UDP,53/TCP 3h
registry-console 172.30.190.63 <none> 9000/TCP 3h
router 172.30.197.135 <none> 80/TCP,443/TCP,1936/TCP 3h
When we SSH directly on the node-1 where the registry and router are running, we can access the registry without problem and we can push some images. Exactly what is here described: docs.openshift.org/latest/install_config/registry/accessing_registry.html
Now we cannot access the registry for other hosts (master or node-2) and we really do not understand how we can make the registry accessible.... We have of course read: docs.openshift.org/latest/install_config/registry/securing_and_exposing_registry.html#access-insecure-registry-by-exposing-route
We have used this command:
oc expose service docker-registry --hostname=<hostname> -n default
The documentation says: You must be able to resolve this name externally via DNS to the router’s IP address.
As the router does not have any EXTERNAL-IP address attached to it, we do not understand how to reach it.
Is there any oc or oadm command for exposing the router through an external-ip address?
Thanks a lot in advance
Emmanuel
Based on your stated configuration I would expect the path to your UI/API for Openshift (openshift.yourdomain.com) to be routed to the same IP as your node-1, because that is where you are running the router.
If that is the case then you would point the hostname you are passing via the command in DNS to the same IP, or as a CNAME to that host.
oc expose service docker-registry --hostname=<hostname> -n default
In a larger setup with dedicated set of load balancer (lb) nodes you might have a specific A record for the set. You could then have the hostname be a CNAME to that record.