Kubernetes Dynamic Provisioning Using Dedicated GlusterFS and Heketi

• Refer here to install Heketi: Complete Example of Dynamic Provisioning Using Dedicated GlusterFS
• How To Configure Kubernetes Dynamic Volume Provisioning With Heketi & GlusterFS
  

Kubernetes Tutorial

Additional Concepts:

• Kubernetes Networking Guide for Beginners
  
• Kubernetes Networking
  
• Node affinity and Inter-pod affinity and anti-affinity
• PodDisruptionBudgets

Install a Kubernetes Cluster

• Using kube-router as Pod Network

kubeadm init  --pod-network-cidr 10.5.0.0/16
kubectl apply -f https://raw.githubusercontent.com/cloudnativelabs/kube-router/master/daemonset/kubeadm-kuberouter.yaml

• Kubernetes Command Line Bash Completion
• Install k8s Minikube on top of KVM on Debian 9
• --
• [Flannel as Pod Network seems not working] How To Install A Kubernetes Cluster On CentOS 7 with flannel as Pod Network and official

Troubleshooting

• Kubernetes Troubleshooting Walkthrough - Pending Pods (issues like not enough CPU, memory)
• Debugging DNS Resolution
  

PersistentVolume and PersistentVolumeClaim

• Configure a Pod to Use a PersistentVolume for Storage
• Troubleshooting: Change PV status from Released to Available: check stackoverflow

kubectl patch pv pv-name -p '{"spec":{"claimRef": null}}'

• Troubleshooting:  PV is stuck at terminating after PVC is deleted (This happens when persistent volume is protected.)

kubectl patch pvc PVC_NAME -p '{"metadata":{"finalizers": []}}' --type=merge

Using GlusterFS with Kubernetes

• Complete Example Using GlusterFS and Persistent Volume and Claim in OpenShift and Kubernetes using GlusterFS Volume Plugin
  
• 
  

StatefulSet

• StatefulSet Basics
  
  

Set Up a Private Docker Registry on CentOS

Tutorial refer to here: How To Set Up a Private Docker Registry on Ubuntu 18.04

Also check Sharing docker images without a registry

Enable sshd service on CentOS7-systemd docker image

1. Build a centos7-systemd docker base image refer to official centos on docker hub

Dockerfile for systemd base image

FROM centos:7.8.2003
ENV container docker
RUN (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == \
systemd-tmpfiles-setup.service ] || rm -f $i; done); \
rm -f /lib/systemd/system/multi-user.target.wants/*;\
rm -f /etc/systemd/system/*.wants/*;\
rm -f /lib/systemd/system/local-fs.target.wants/*; \
rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
rm -f /lib/systemd/system/basic.target.wants/*;\
rm -f /lib/systemd/system/anaconda.target.wants/*;
VOLUME [ "/sys/fs/cgroup" ]
CMD ["/usr/sbin/init"]

Build your base image

$ docker build --rm -t local/centos7-systemd .

2.  Build image with sshd service based upon above base image

Dockerfile of centos7-systemd-sshd 

FROM local/centos7-systemd
RUN yum -y install openssh-server openssh-clients; systemctl enable sshd.service;
CMD ["/usr/sbin/init"]

Build image

docker build --rm -t local/centos7-systemd-sshd .

3. Run a container of centos7-systemd-sshd refer to stackflow

docker run -it -d --name node2 --privileged -e container=docker \
-v /sys/fs/cgroup:/sys/fs/cgroup:ro local/centos7-systemd-sshd /usr/sbin/init

Enter into container's terminal:

docker exec -it node2 bash

End

Docker Tutorials

Basic Tutorials:

1. Docker Build: A Beginner’s Guide to Building Docker Images
2. Docker Curriculum
3. Awesome Docker

Docker Volume: 

1. Understanding Docker Volumes with an example 
2. Docker Tutorial Series : Part 7 : Data Volumes [recommended]

General and comprehensive  Tutorial:

1. Docker Tutorial Series (Recommended,  there are a lot of content)
2. Container Tutorials (Looks like a really good resources)

Configure docker image autorestart:

# In order to enable a restart policy, you need to use the --restart argument when executing docker run
docker run -dit --restart unless-stopped httpd

# Or configure a running container
# unless-stopped: The container would always be restarted unless it was manually stopped
docker update --restart unless-stopped container_id

• How to Start Docker Containers Automatically After a Reboot? 
  

Content from Docker Tutorial Series : 

Part 1 — Installation

Part 2 — Basic Commands

Part 3 — More on Images and Containers

Part 4 — Docker Hub

Part 5 — Building your own Docker Images

Part 6 — Docker Private Registry

Part 7 — Data Volumes

Part 8 — Linking Containers

Part 9 — Writing a Dockerfile

Part 10 — Docker Swarm Tutorial

Part 11 — Docker Swarm on Google Compute Engine

Part 12 — Getting Started with Kubernetes using Minikube

Part 13 — Docker Management Commands

Appendix

Docker : Learning Resources

Docker Use Cases

Learning Docker ? Move To The Cloud !