• Docker-compose Yum Install Centos 7
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• Centos 8 Install Docker-compose
• Docker Compose Install Centos 7

Docker Compose is a tool used to define and run multi-container Docker applications. Users utilize this software to launch, execute, communicate, and close containers with a single coordinated command. This tutorial will show you how to install Docker Compose on CentOS 7. The list returned depends on which repositories are enabled, and is specific to your version of CentOS (indicated by the.el7 suffix in this example). Install a specific version by its fully qualified package name, which is the package name (docker-ce) plus the version string (2nd column) starting at the first colon (:), up to the first hyphen, separated by a hyphen (-).

Elasticsearch is also available as Docker images.The images use centos:8 as the base image.

A list of all published Docker images and tags is available atwww.docker.elastic.co. The source filesare inGithub.

This package contains both free and subscription features.Start a 30-day trial to try out all of the features.

Docker is a containerization platform that allows you to quickly build, test and deploy applications as portable, self-sufficient containers that can run virtually anywhere. In this tutorial, we’ll explain how to install Docker on Debian 10 Buster and explore the basic Docker concepts and commands. Install Docker on Debian #. To accomodate environments where memory is scarce (Docker for Mac has only 2 GB available by default), the Heap Size allocation is capped by default to 256MB per service in the docker-compose.yml file. If you want to override the default JVM configuration, edit the matching environment variable(s) in the docker-compose.yml file.

Obtaining Elasticsearch for Docker is as simple as issuing a docker pull commandagainst the Elastic Docker registry.

To start a single-node Elasticsearch cluster for development or testing, specifysingle-node discovery to bypass the bootstrap checks:

To get a three-node Elasticsearch cluster up and running in Docker,you can use Docker Compose:

Docker-compose Yum Install Centos 7

This sample docker-compose.yml file uses the ES_JAVA_OPTSenvironment variable to manually set the heap size to 512MB. We do not recommendusing ES_JAVA_OPTS in production. See Manually set the heap size.

This sample Docker Compose file brings up a three-node Elasticsearch cluster.Node es01 listens on localhost:9200 and es02 and es03 talk to es01 over a Docker network.

Please note that this configuration exposes port 9200 on all network interfaces, and given howDocker manipulates iptables on Linux, this means that your Elasticsearch cluster is publically accessible,potentially ignoring any firewall settings. If you don’t want to expose port 9200 and instead usea reverse proxy, replace 9200:9200 with 127.0.0.1:9200:9200 in the docker-compose.yml file.Elasticsearch will then only be accessible from the host machine itself.

The Docker named volumesdata01, data02, and data03 store the node data directories so the data persists across restarts.If they don’t already exist, docker-compose creates them when you bring up the cluster.

1. Make sure Docker Engine is allotted at least 4GiB of memory.In Docker Desktop, you configure resource usage on the Advanced tab in Preference (macOS)or Settings (Windows).

   Docker Compose is not pre-installed with Docker on Linux.See docs.docker.com for installation instructions:Install Compose on Linux

2. Run docker-compose to bring up the cluster:

3. Submit a _cat/nodes request to see that the nodes are up and running:

Log messages go to the console and are handled by the configured Docker logging driver.By default you can access logs with docker logs. If you would prefer the Elasticsearchcontainer to write logs to disk, set the ES_LOG_STYLE environment variable to file.This causes Elasticsearch to use the same logging configuration as other Elasticsearch distribution formats.

To stop the cluster, run docker-compose down.The data in the Docker volumes is preserved and loadedwhen you restart the cluster with docker-compose up.To delete the data volumes when you bring down the cluster,specify the -v option: docker-compose down -v.

See Encrypting communications in an Elasticsearch Docker Container andRun the Elastic Stack in Docker with TLS enabled.

The following requirements and recommendations apply when running Elasticsearch in Docker in production.

The vm.max_map_count kernel setting must be set to at least 262144 for production use.

How you set vm.max_map_count depends on your platform:

• Linux

  The vm.max_map_count setting should be set permanently in /etc/sysctl.conf:

  To apply the setting on a live system, run:

• macOS with Docker for Mac

  The vm.max_map_count setting must be set within the xhyve virtual machine:

  1. From the command line, run:

  2. Press enter and use`sysctl` to configure vm.max_map_count:

  3. To exit the screen session, type Ctrl a d.

• Windows and macOS with Docker Desktop

  The vm.max_map_count setting must be set via docker-machine:

• Windows with Docker Desktop WSL 2 backend

  The vm.max_map_count setting must be set in the docker-desktop container:

By default, Elasticsearch runs inside the container as user elasticsearch usinguid:gid 1000:0.

One exception is Openshift,which runs containers using an arbitrarily assigned user ID.Openshift presents persistent volumes with the gid set to 0, which works without any adjustments.

If you are bind-mounting a local directory or file, it must be readable by the elasticsearch user.In addition, this user must have write access to the config, data and log dirs(Elasticsearch needs write access to the config directory so that it can generate a keystore).A good strategy is to grant group access to gid 0 for the local directory.

For example, to prepare a local directory for storing data through a bind-mount:

You can also run an Elasticsearch container using both a custom UID and GID. Unless youbind-mount each of the config, data` and logs directories, you must passthe command line option --group-add 0 to docker run. This ensures that the userunder which Elasticsearch is running is also a member of the root (GID 0) group inside thecontainer.

As a last resort, you can force the container to mutate the ownership ofany bind-mounts used for the data and log dirs through theenvironment variable TAKE_FILE_OWNERSHIP. When you do this, they will be owned byuid:gid 1000:0, which provides the required read/write access to the Elasticsearch process.

Increased ulimits for nofile and nprocmust be available for the Elasticsearch containers.Verify the init systemfor the Docker daemon sets them to acceptable values.

To check the Docker daemon defaults for ulimits, run:

If needed, adjust them in the Daemon or override them per container.For example, when using docker run, set:

Swapping needs to be disabled for performance and node stability.For information about ways to do this, see Disable swapping.

If you opt for the bootstrap.memory_lock: true approach,you also need to define the memlock: true ulimit in theDocker Daemon,or explicitly set for the container as shown in the sample compose file.When using docker run, you can specify:

The image exposesTCP ports 9200 and 9300. For production clusters, randomizing thepublished ports with --publish-all is recommended,unless you are pinning one container per host.

By default, Elasticsearch automatically sizes JVM heap based on a nodes’sroles and the total memory available to the node’s container. Werecommend this default sizing for most production environments. If needed, youcan override default sizing by manually setting JVM heap size.

To manually set the heap size in production, bind mount a JVMoptions file under /usr/share/elasticsearch/config/jvm.options.d thatincludes your desired heap size settings.

For testing, you can also manually set the heap size using the ES_JAVA_OPTSenvironment variable. For example, to use 16GB, specify -eES_JAVA_OPTS='-Xms16g -Xmx16g' with docker run. The ES_JAVA_OPTS variableoverrides all other JVM options. The ES_JAVA_OPTS variable overrides all otherJVM options. We do not recommend using ES_JAVA_OPTS in production. Thedocker-compose.yml file above sets the heap size to 512MB.

Pin your deployments to a specific version of the Elasticsearch Docker image. Forexample docker.elastic.co/elasticsearch/elasticsearch:7.12.0.

You should use a volume bound on /usr/share/elasticsearch/data for the following reasons:

1. The data of your Elasticsearch node won’t be lost if the container is killed
2. Elasticsearch is I/O sensitive and the Docker storage driver is not ideal for fast I/O
3. It allows the use of advancedDocker volume plugins

If you are using the devicemapper storage driver, do not use the default loop-lvm mode.Configure docker-engine to usedirect-lvm.

Consider centralizing your logs by using a differentlogging driver. Alsonote that the default json-file logging driver is not ideally suited forproduction use.

When you run in Docker, the Elasticsearch configuration files are loaded from/usr/share/elasticsearch/config/.

To use custom configuration files, you bind-mount the filesover the configuration files in the image.

You can set individual Elasticsearch configuration parameters using Docker environment variables.The sample compose file and thesingle-node example use this method.

To use the contents of a file to set an environment variable, suffix the environmentvariable name with _FILE. This is useful for passing secrets such as passwords to Elasticsearchwithout specifying them directly.

For example, to set the Elasticsearch bootstrap password from a file, you can bind mount thefile and set the ELASTIC_PASSWORD_FILE environment variable to the mount location.If you mount the password file to /run/secrets/bootstrapPassword.txt, specify:

You can also override the default command for the image to pass Elasticsearch configurationparameters as command line options. For example:

While bind-mounting your configuration files is usually the preferred method in production,you can also create a custom Docker imagethat contains your configuration.

Create custom config files and bind-mount them over the corresponding files in the Docker image.For example, to bind-mount custom_elasticsearch.yml with docker run, specify:

The container runs Elasticsearch as user elasticsearch usinguid:gid 1000:0. Bind mounted host directories and files must be accessible by this user,and the data and log directories must be writable by this user.

By default, Elasticsearch will auto-generate a keystore file for secure settings. Thisfile is obfuscated but not encrypted. If you want to encrypt yoursecure settings with a password, you must use theelasticsearch-keystore utility to create a password-protected keystore andbind-mount it to the container as/usr/share/elasticsearch/config/elasticsearch.keystore. In order to providethe Docker container with the password at startup, set the Docker environmentvalue KEYSTORE_PASSWORD to the value of your password. For example, a dockerrun command might have the following options:

In some environments, it might make more sense to prepare a custom image that containsyour configuration. A Dockerfile to achieve this might be as simple as:

You could then build and run the image with:

Some plugins require additional security permissions.You must explicitly accept them either by:

• Attaching a tty when you run the Docker image and allowing the permissions when prompted.
• Inspecting the security permissions and accepting them (if appropriate) by adding the --batch flag to the plugin install command.

See Plugin managementfor more information.

You now have a test Elasticsearch environment set up. Before you startserious development or go into production with Elasticsearch, you must do some additionalsetup:

• Learn how to configure Elasticsearch.
• Configure important Elasticsearch settings.
• Configure important system settings.

Installing Docker on Ubuntu is simple because Ubuntu provides Docker in its repositories. However, Docker is not available in CentOS's default repositories.

Fret not, there are three ways you can install docker on a CentOS Linux system.

• Using docker's repository
• Downloading the RPM
• Using helper scripts

Here, I'll walk you through the installation process of Docker CE using docker's RPM repository.

Docker CE stands for Docker Community Edition. This is the free and open source version of Docker. There is Docker EE (Enterprise Edition) with paid support. Most of the world uses Docker CE and it is often considered synonymous to Docker.

Installing Docker on CentOS

Before going any further, make sure you have the system updated. You can update the CentOS using:

Step 1: Add the official repository

Add docker's official repository using the following command

You should also update the package cache after adding a new repository:

Step 2: Install Docker CE

The trouble with using a custom repository is that it may have dependency issue if you try installing the latest version of docker-ce.

For example, when I check the available versions of docker-ce with this command:

I got docker-ce-3:19.03.9-3.el7 as the latest version. But the problem in installing the latest version is that it depends on containerd.io version >=1.2.2-3. Now, this version of containerd.io is not available in CentOS 8.

Docker Compose Install Centos 6

To avoid this dependency cycle and battling them manually, you can use the --nobest option of the dnf command.

It will check the latest version of docker-ce but when it finds the dependency issue, it checks the next available version of docker-ce. Basically, it helps you automatically install the most suitable package version with all the dependencies satisfied.

To install docker in CentOS without getting a migraine, try this command and see the magic unfold on your terminal screen:

You'll be prompted to import a GPG key, make sure the key matches to 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35 before entering 'y'.

containerd.io is a daemon for managing containers. Docker is just one form of Linux containers. To make the various types of container images portable, Open Container Initiative has defined some standards. containerd is used for managing the container images conforming to OCI standard.

Setting up docker on CentOS

Alright! You have docker installed but it's not yet ready to be used yet. You'll have to do some basic configurations before it can be used smoothly.

Run docker without sudo

You can run docker without any sudo privileges by adding your user to the docker group.

The docker group should already exist. Check that using the following command:

If this outputs nothing, create the docker group using groupadd command like this:

Now add your user to the docker group using the usermod command:

Change the user_name in the above command with the intended user name.

Now log out and log back in for the group change to take effect.

Start docker daemon

Docker is installed. Your user has been added to the docker group. But that's not enough to run docker yet.

Before you can run any container, the docker daemon needs to be running. The docker daemon is the program that manages all the containers, volumes, networks etc. In other words, the daemon does all the heavy lifting.

Start the docker daemon using:

Centos 8 Install Docker-compose

You can also enable docker daemon to start automatically at boot time:

Verify docker installation by running a sample container

Everything is done. It's time to test whether the installation was successful or not by running a docker container.

To verify, you can run the cliché hello-world docker container. It is a tiny docker image and perfect for quickly testing a docker installation.

If everything is fine, you should see an output like this:

Here's what the command is doing behind the hood:

• The docker client, i.e. the command line tool that you just used, contacted the docker daemon.
• The daemon looked for hello-world docker image in the local system. Since it doesn't find the image, it pulls it from Docker Hub.
• The engine creates the container with all the options you provided through the client's command line options.

This hello-world image is used just for testing a docker installation. If you want a more useful container, you can try running Nginx server in a container like this:

Once the command is done running, open up a browser and go to http://your_ip_address:56788. I hope you know how to know your IP address in Linux.

You should see nginx server running. You can stop the container now.

I hope this tutorial helped you in installing docker on CentOS. Do subscribe for more Docker tutorials and DevOps tips.

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