Tech Notes – Page 17 – Kev's Development Toolbox

December 17, 2017November 10, 2018

kubernetes : kubectl useful commands

Working through the interactive tutorial here is a good reference for kubectl usage.

A few notes for reference:

Copy master node config to a remote machine (from here):

scp root@<master ip>:/etc/kubernetes/admin.conf .

All of the commands if running on a remote machine can use the copied conf file by passing: --kubeconfig ./admin.conf

Query nodes in the cluster:

kubectl get nodes

Show current cluster info:

./kubectl cluster-info

Kubernetes master is running at https://192.168.1.80:6443

KubeDNS is running at https://192.168.1.80:6443/api/v1/namespaces/kube-system/services/kube-dns/proxy

From the interactive tutorial:

Run kubernetes-bootcamp:

kubectl run kubernetes-bootcamp --image=docker.io/jocatalin/kubernetes-bootcamp:v1 --port=8080

Pods:

kubectl get pods
kubectl describe pod podname
kubectl delete pod podname

Deployments:

kubectl get deployments
kubectl describe deployment deploymentname
kubectl delete deployment deploymentname

Get logs

kubectl logs podname

October 22, 2017October 22, 2017

Installing Grafana on Ubuntu 16.06

Following the install instructions here:

Add the repo to /etc/apt/sources.list and install with apt-get:

deb https://packagecloud.io/grafana/stable/debian/ jessie main

Add key:

curl https://packagecloud.io/gpg.key | sudo apt-key add -

Update and install:

sudo apt-get update
sudo apt-get install grafana

Start up the server service:

sudo service grafana-server start

To start at boot:

sudo update-rc.d grafana-server defaults

Up!

October 21, 2017October 21, 2017

Configuring Gitlab installation

After installing GitLab, by default your project urls are @gitlab.example.com:

Your server domain is configured in the /etc/gitlab/gitlab.rb file, as described in the docs here.

To pick up your changes:

sudo gitlab-ctl reconfigure

October 21, 2017

Allowing user on CentOS to run docker command without sudo

Out of the box for a Docker install on CentOS 7, you have to sudo the docker command to interact with Docker. Per the post-install steps here, create a docker group and add your user to that group:

sudo groupadd docker

sudo usermod -aG docker youruser

Logging off and back on again, you should now be able to run the docker command without sudo.

On CentOS 7 this still didn’t work for me. Following this post, it appeared that docker.sock was owned by root and in the group root:

$ ls -l /var/run/docker.sock

srw-rw---- 1 root root 0 Oct 21 15:42 /var/run/docker.sock

Changing the group ownership:

$ sudo chown root:docker /var/run/docker.sock

$ ls -l /var/run/docker.sock

srw-rw---- 1 root docker 0 Oct 21 15:42 /var/run/docker.sock

After logging back on, now can run docker commands without sudo.