Detailed explanation of the installation commands and usage of Docker and FastDFS

Docker Features

1) Quick to get started

It only takes a few minutes for users to "Dockerize" their programs. Docker relies on a "copy-on-write" model, which makes it very quick to modify applications. It can be said that it reaches the state of "change the code as you wish".

You can then create a container to run your application. Most Docker containers start in less than a second. By removing the overhead of the hypervisor, Docker containers have high performance, and more containers can be run on the same host machine, allowing users to make the best possible use of system resources.

2) Logical classification of responsibilities

With Docker, developers only need to worry about the applications running in the container, and operators only need to worry about how to manage the container. The purpose of Docker design is to enhance the consistency between the development environment where developers write code and the production environment where applications are deployed. This will reduce the perception that “everything was normal during development, so it must be an operation and maintenance problem (the test environment is normal, but problems occurred after going online, so it must be an operation and maintenance problem)”

3) Fast and efficient development life cycle

One of Docker's goals is to shorten the code development, testing, deployment, and online operation cycle, making your applications portable, easy to build, and easy to collaborate on. (To put it simply, Docker is like a box that can hold many objects. If you need these objects, you can take them out directly from the big box without having to take them out one by one from the box.)

4) Encourage the use of service-oriented architecture

Docker also encourages service-oriented architecture and microservices architecture. Docker recommends that a single container run only one application or process, thus forming a distributed application model. In this model, applications or services can be represented as a series of internally interconnected containers, making it very simple to deploy distributed applications, expand or debug applications, and also improving the introspection of the program. (Of course, you can run multiple applications in one container)

What to do with Docker

Containers provide isolation and can provide a good sandbox environment for various tests. Furthermore, the container

The "standard" nature of PHP makes it ideal for creating building blocks for services. Some application scenarios of Docker are as follows:

• Speed ​​up local development and build processes, making them more efficient and lightweight. Local developers can build, run, and share Docker containers. Containers can be built in a development environment and then easily pushed to a test environment and eventually to a production environment.
• It enables independent services or applications to achieve the same operating results in different environments. This is especially useful in service-oriented architectures and deployments that rely heavily on microservices.
• Use Docker to create an isolated environment for testing. For example, use a continuous integration tool like Jenkins CI to start a container for testing.
• Docker allows developers to build a complex program or architecture on their local machine for testing, rather than deploying and testing it in a production environment from the beginning.

Installation and Operation

1. Install Docker in Ubuntu

Update Ubuntu's apt source index

sudo apt-get update

Install package to allow apt to use repositories over HTTPS

sudo apt-get install \
  apt-transport-https \
  ca-certificates \
  curl \
  software-properties-common

Add Docker official GPG key

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

Setting up the Docker stable repository

sudo add-apt-repository \
  "deb [arch=amd64] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) \
  stable"

After adding the repository, update the apt source index

sudo apt-get update

Install the latest version of Docker CE (Community Edition)

sudo apt-get install docker-ce

Check whether Docker CE is installed correctly

sudo docker run hello-world

The following message appears, indicating that the installation is successful

To avoid typing sudo every time you run a command, you can set user permissions. Note that you must log out and log in again after executing the command.

sudo usermod -a -G docker $USER

2. Start and stop

After installing Docker, the Docker service is started by default. If you need to manually control the start and stop of the Docker service, you can execute the following command

# Start Docker
sudo service docker start

# Stop Docker
sudo service docker stop

# Restart Docker
sudo service docker restart

3. Docker image operation

1. List images

docker image ls

2. Pull the image

To obtain a certain image, we can use the pull command to pull the image from the warehouse to the local, such as

docker image pull library/hello-world

Since the image files officially provided by Docker are all placed in the library group, it is the default group and can be omitted. Therefore, the above command can be written as follows.

docker image pull hello-world

3. Delete the image

docker image rm image name or image id

4. Docker container operation

Create a container

docker run [option] image name [command passed to the startup container]

Description of common optional parameters:

• -i means running the container in "interactive mode"
• -t means that the container will enter its command line after it starts. After adding these two parameters, you can log in to the container after it is created. That is, allocate a pseudo terminal.
• --name Name the created container
• -v indicates the directory mapping relationship (the former is the host directory, and the latter is the directory mapped to the host, that is, host directory: directory in the container). Multiple -v can be used to map multiple directories or files. Note: It is best to do directory mapping, make changes on the host machine, and then share it to the container.
• -d If you add the -d parameter after run, a guarded container will be created and run in the background (in this way, you will not automatically log in to the container after creating it. If you only add the -i -t parameters, you will automatically enter the container after creation).
• -p means port mapping. The former is the host port and the latter is the mapping port in the container. You can use multiple -p to map multiple ports.
• -e sets environment variables for the container
• --network=host means mapping the host's network environment to the container, and the container's network is the same as the host's

Interactive Containers

For example, create an interactive container and name it myubuntu

docker run -it --name=myubuntu ubuntu /bin/bash

You can execute Linux commands at will in the container, which is an Ubuntu environment. When the exit command is executed to exit, the container will also stop.

Guarded Container

Create a daemon container: If a container needs to run for a long time, we can create a daemon container. When you exit from within the container, the container will not stop.

docker run -dit --name=myubuntu2 ubuntu

Enter the running container

docker exec -it container name or container id The first command executed after entering

like

docker exec -it myubuntu2 /bin/bash

View Container

# List the containers running on this machine docker container ls

# List all containers on this machine, including the terminated docker container ls --all

Stopping and starting containers

#Stop an already running container docker container stop container name or container id

# Start a stopped container docker container start container name or container id

# Kill a running container docker container kill container name or container id

Deleting a container

docker container rm container name or container id

5. Save the container as an image

We can save the container as an image with the following command

docker commit container name image name

6. Image backup and migration

We can use the save command to package the image into a file and copy it to others for use

docker save -o Saved file name image name

like

docker save -o ./ubuntu.tar ubuntu

After getting the image file, you can load the image to the local computer through the load method.

docker load -i ./ubuntu.tar

Install FastDFS using Docker

1. Get the image

You can use the existing FastDFS Docker image to run FastDFS.

You can download the image by

docker image pull delron/fastdfs

After loading the image, you can start running FastDFS's tracker and storage.

2. Run the tracker

Execute the following command to start the tracker service

docker run -dti --network=host --name tracker -v /var/fdfs/tracker:/var/fdfs delron/fastdfs tracker

We map the fastDFS tracker running directory to the local /var/fdfs/tracker directory.

Execute the following command to check whether the tracker is running

docker container ls

If you want to stop the tracker service, you can execute the following command

docker container stop tracker

After stopping, re-run the tracker and execute the following command

docker container start tracker

3. Run storage

Execute the following command to start the storage service

docker run -dti --network=host --name storage -e TRACKER_SERVER=10.211.55.5:22122 -v /var/fdfs/storage:/var/fdfs delron/fastdfs storage

• TRACKER_SERVER=The local IP address: 22122. Do not use 127.0.0.1 for the local IP address.
• We map the fastDFS storage running directory to the local /var/fdfs/storage directory

Execute the following command to check whether storage is running

docker container ls

If you want to stop the storage service, you can execute the following command

docker container stop storage

After stopping, re-run storage and execute the following command

docker container start storage

Note: If you cannot rerun the operation, delete the fdfs_storaged.pid file in the /var/fdfs/storage/data directory and rerun storage.

The above is the full content of this article. I hope it will be helpful for everyone’s study. I also hope that everyone will support 123WORDPRESS.COM.