Docker Persistent Storage
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Communication among Docker images
By default the host machine has no access to the files inside the Docker container because Docker containers are isolated from the host machine by default.
However, we have a couple of ways to get around this.
- The most common way is to have Docker specify environment variables inside the Docker container. Then, the code running inside the Docker container will check the environment variables on startup and use them to configure itself accordingly.
- Another commonly used method is a Docker data volume as we'll see in subsequent sections of this page.
- The last way of communicating with a Docker container is using links or port forwarding.
Data volumes
Data volumes are designed to persist data, independent of the container's life cycle.
Docker therefore never automatically delete volumes when we remove a container, nor will it "garbage collect" volumes that are no longer referenced by a container.
Adding a data volume
Though we executed docker run commands with various argument combinations in the previous chapter(More on docker run command (docker run -it, docker run --rm, etc.)), docker run was not doing useful operations.
So, in this chapter, we'll learn more about docker run commands that doing more useful things: we're going to run docker run command with -v argument:
$ docker container run -it --name yaong -v /mydata ubuntu:latest /bin/bash
Let's create files under the /mydata folder:
root@58d7df37dc80:/# cd /mydata root@58d7df37dc80:/mydata# touch a b c root@58d7df37dc80:/mydata#
Get out of the container (Ctrl + P + Q) without stopping it.
Locating a volume
Let's check our docker volume:
$ docker volume ls DRIVER VOLUME NAME local 86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a
We can locate the volume on the host by utilizing the "docker inspect" or "docker volume inspect" command. The output will provide details on the container configurations including the volumes:
$ docker inspect yaong
...
"Mounts": [
{
"Type": "volume",
"Name": "86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a",
"Source": "/var/lib/docker/volumes/86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a/_data",
"Destination": "/mydata",
"Driver": "local",
"Mode": "",
"RW": true,
"Propagation": ""
}
],
...
Or:
$ docker volume inspect 86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a
[
{
"CreatedAt": "2018-10-15T19:21:48-07:00",
"Driver": "local",
"Labels": null,
"Mountpoint": "/var/lib/docker/volumes/86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a/_data",
"Name": "86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a",
"Options": null,
"Scope": "local"
}
]
Let's check if the files we created on the container are really in the host file system:
$ sudo su - # ls /var/lib/docker/volumes/86f9c58b9aaf11b4eccf81fabe2e91ccdca9b2a3bdf21f8639d0b18e7925628a/_data a b c
Yes, the files 'a','b', and 'c' are there in our host machine!
Mount a host directory as a data volume
We can mount a directory from our Docker host into a container.
We have three files 'a', 'b', and 'c' in host-volume folder:
$ ls host-volume d e f
Now we want to mount the directory to our Docker container:
$ docker run -it --name=yaong2 -v /home/k/host-volume:/opt/host-volume ubuntu:latest /bin/bash
This will mount the host directory, /home/k/host-volume, into the container at /opt/host-volume.
We can check if our container is sharing the volume:
root@63ec4bb5c857:/# ls /opt/host-volume d e f
Let's remove the 'c' file and check the host file system if it's really been removed:
root@63ec4bb5c857:/# rm /opt/host-volume/d root@63ec4bb5c857:/# ls /opt/host-volume e f
Type "Ctrl + P + Q" to exit without stopping the container:
$ ls /home/k/host-volume e f
Yes, we can see clearly the file sharing is working!
Stop the container:
$ docker container stop yaong2 yaong2
Docker & K8s
- Docker install on Amazon Linux AMI
- Docker install on EC2 Ubuntu 14.04
- Docker container vs Virtual Machine
- Docker install on Ubuntu 14.04
- Docker Hello World Application
- Nginx image - share/copy files, Dockerfile
- Working with Docker images : brief introduction
- Docker image and container via docker commands (search, pull, run, ps, restart, attach, and rm)
- More on docker run command (docker run -it, docker run --rm, etc.)
- Docker Networks - Bridge Driver Network
- Docker Persistent Storage
- File sharing between host and container (docker run -d -p -v)
- Linking containers and volume for datastore
- Dockerfile - Build Docker images automatically I - FROM, MAINTAINER, and build context
- Dockerfile - Build Docker images automatically II - revisiting FROM, MAINTAINER, build context, and caching
- Dockerfile - Build Docker images automatically III - RUN
- Dockerfile - Build Docker images automatically IV - CMD
- Dockerfile - Build Docker images automatically V - WORKDIR, ENV, ADD, and ENTRYPOINT
- Docker - Apache Tomcat
- Docker - NodeJS
- Docker - NodeJS with hostname
- Docker Compose - NodeJS with MongoDB
- Docker - Prometheus and Grafana with Docker-compose
- Docker - StatsD/Graphite/Grafana
- Docker - Deploying a Java EE JBoss/WildFly Application on AWS Elastic Beanstalk Using Docker Containers
- Docker : NodeJS with GCP Kubernetes Engine
- Docker : Jenkins Multibranch Pipeline with Jenkinsfile and Github
- Docker : Jenkins Master and Slave
- Docker - ELK : ElasticSearch, Logstash, and Kibana
- Docker - ELK 7.6 : Elasticsearch on Centos 7
- Docker - ELK 7.6 : Filebeat on Centos 7
- Docker - ELK 7.6 : Logstash on Centos 7
- Docker - ELK 7.6 : Kibana on Centos 7
- Docker - ELK 7.6 : Elastic Stack with Docker Compose
- Docker - Deploy Elastic Cloud on Kubernetes (ECK) via Elasticsearch operator on minikube
- Docker - Deploy Elastic Stack via Helm on minikube
- Docker Compose - A gentle introduction with WordPress
- Docker Compose - MySQL
- MEAN Stack app on Docker containers : micro services
- MEAN Stack app on Docker containers : micro services via docker-compose
- Docker Compose - Hashicorp's Vault and Consul Part A (install vault, unsealing, static secrets, and policies)
- Docker Compose - Hashicorp's Vault and Consul Part B (EaaS, dynamic secrets, leases, and revocation)
- Docker Compose - Hashicorp's Vault and Consul Part C (Consul)
- Docker Compose with two containers - Flask REST API service container and an Apache server container
- Docker compose : Nginx reverse proxy with multiple containers
- Docker & Kubernetes : Envoy - Getting started
- Docker & Kubernetes : Envoy - Front Proxy
- Docker & Kubernetes : Ambassador - Envoy API Gateway on Kubernetes
- Docker Packer
- Docker Cheat Sheet
- Docker Q & A #1
- Kubernetes Q & A - Part I
- Kubernetes Q & A - Part II
- Docker - Run a React app in a docker
- Docker - Run a React app in a docker II (snapshot app with nginx)
- Docker - NodeJS and MySQL app with React in a docker
- Docker - Step by Step NodeJS and MySQL app with React - I
- Installing LAMP via puppet on Docker
- Docker install via Puppet
- Nginx Docker install via Ansible
- Apache Hadoop CDH 5.8 Install with QuickStarts Docker
- Docker - Deploying Flask app to ECS
- Docker Compose - Deploying WordPress to AWS
- Docker - WordPress Deploy to ECS with Docker-Compose (ECS-CLI EC2 type)
- Docker - WordPress Deploy to ECS with Docker-Compose (ECS-CLI Fargate type)
- Docker - ECS Fargate
- Docker - AWS ECS service discovery with Flask and Redis
- Docker & Kubernetes : minikube
- Docker & Kubernetes 2 : minikube Django with Postgres - persistent volume
- Docker & Kubernetes 3 : minikube Django with Redis and Celery
- Docker & Kubernetes 4 : Django with RDS via AWS Kops
- Docker & Kubernetes : Kops on AWS
- Docker & Kubernetes : Ingress controller on AWS with Kops
- Docker & Kubernetes : HashiCorp's Vault and Consul on minikube
- Docker & Kubernetes : HashiCorp's Vault and Consul - Auto-unseal using Transit Secrets Engine
- Docker & Kubernetes : Persistent Volumes & Persistent Volumes Claims - hostPath and annotations
- Docker & Kubernetes : Persistent Volumes - Dynamic volume provisioning
- Docker & Kubernetes : DaemonSet
- Docker & Kubernetes : Secrets
- Docker & Kubernetes : kubectl command
- Docker & Kubernetes : Assign a Kubernetes Pod to a particular node in a Kubernetes cluster
- Docker & Kubernetes : Configure a Pod to Use a ConfigMap
- AWS : EKS (Elastic Container Service for Kubernetes)
- Docker & Kubernetes : Run a React app in a minikube
- Docker & Kubernetes : Minikube install on AWS EC2
- Docker & Kubernetes : Cassandra with a StatefulSet
- Docker & Kubernetes : Terraform and AWS EKS
- Docker & Kubernetes : Pods and Service definitions
- Docker & Kubernetes : Service IP and the Service Type
- Docker & Kubernetes : Kubernetes DNS with Pods and Services
- Docker & Kubernetes : Headless service and discovering pods
- Docker & Kubernetes : Scaling and Updating application
- Docker & Kubernetes : Horizontal pod autoscaler on minikubes
- Docker & Kubernetes : From a monolithic app to micro services on GCP Kubernetes
- Docker & Kubernetes : Rolling updates
- Docker & Kubernetes : Deployments to GKE (Rolling update, Canary and Blue-green deployments)
- Docker & Kubernetes : Slack Chat Bot with NodeJS on GCP Kubernetes
- Docker & Kubernetes : Continuous Delivery with Jenkins Multibranch Pipeline for Dev, Canary, and Production Environments on GCP Kubernetes
- Docker & Kubernetes : NodePort vs LoadBalancer vs Ingress
- Docker & Kubernetes : MongoDB / MongoExpress on Minikube
- Docker & Kubernetes : Load Testing with Locust on GCP Kubernetes
- Docker & Kubernetes : MongoDB with StatefulSets on GCP Kubernetes Engine
- Docker & Kubernetes : Nginx Ingress Controller on Minikube
- Docker & Kubernetes : Setting up Ingress with NGINX Controller on Minikube (Mac)
- Docker & Kubernetes : Nginx Ingress Controller for Dashboard service on Minikube
- Docker & Kubernetes : Nginx Ingress Controller on GCP Kubernetes
- Docker & Kubernetes : Kubernetes Ingress with AWS ALB Ingress Controller in EKS
- Docker & Kubernetes : Setting up a private cluster on GCP Kubernetes
- Docker & Kubernetes : Kubernetes Namespaces (default, kube-public, kube-system) and switching namespaces (kubens)
- Docker & Kubernetes : StatefulSets on minikube
- Docker & Kubernetes : RBAC
- Docker & Kubernetes Service Account, RBAC, and IAM
- Docker & Kubernetes - Kubernetes Service Account, RBAC, IAM with EKS ALB, Part 1
- Docker & Kubernetes : Helm Chart
- Docker & Kubernetes : My first Helm deploy
- Docker & Kubernetes : Readiness and Liveness Probes
- Docker & Kubernetes : Helm chart repository with Github pages
- Docker & Kubernetes : Deploying WordPress and MariaDB with Ingress to Minikube using Helm Chart
- Docker & Kubernetes : Deploying WordPress and MariaDB to AWS using Helm 2 Chart
- Docker & Kubernetes : Deploying WordPress and MariaDB to AWS using Helm 3 Chart
- Docker & Kubernetes : Helm Chart for Node/Express and MySQL with Ingress
- Docker & Kubernetes : Deploy Prometheus and Grafana using Helm and Prometheus Operator - Monitoring Kubernetes node resources out of the box
- Docker & Kubernetes : Deploy Prometheus and Grafana using kube-prometheus-stack Helm Chart
- Docker & Kubernetes : Istio (service mesh) sidecar proxy on GCP Kubernetes
- Docker & Kubernetes : Istio on EKS
- Docker & Kubernetes : Istio on Minikube with AWS EC2 for Bookinfo Application
- Docker & Kubernetes : Deploying .NET Core app to Kubernetes Engine and configuring its traffic managed by Istio (Part I)
- Docker & Kubernetes : Deploying .NET Core app to Kubernetes Engine and configuring its traffic managed by Istio (Part II - Prometheus, Grafana, pin a service, split traffic, and inject faults)
- Docker & Kubernetes : Helm Package Manager with MySQL on GCP Kubernetes Engine
- Docker & Kubernetes : Deploying Memcached on Kubernetes Engine
- Docker & Kubernetes : EKS Control Plane (API server) Metrics with Prometheus
- Docker & Kubernetes : Spinnaker on EKS with Halyard
- Docker & Kubernetes : Continuous Delivery Pipelines with Spinnaker and Kubernetes Engine
- Docker & Kubernetes : Multi-node Local Kubernetes cluster : Kubeadm-dind (docker-in-docker)
- Docker & Kubernetes : Multi-node Local Kubernetes cluster : Kubeadm-kind (k8s-in-docker)
- Docker & Kubernetes : nodeSelector, nodeAffinity, taints/tolerations, pod affinity and anti-affinity - Assigning Pods to Nodes
- Docker & Kubernetes : Jenkins-X on EKS
- Docker & Kubernetes : ArgoCD App of Apps with Heml on Kubernetes
- Docker & Kubernetes : ArgoCD on Kubernetes cluster
- Docker & Kubernetes : GitOps with ArgoCD for Continuous Delivery to Kubernetes clusters (minikube) - guestbook
Ph.D. / Golden Gate Ave, San Francisco / Seoul National Univ / Carnegie Mellon / UC Berkeley / DevOps / Deep Learning / Visualization
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