How to install ElasticSearch on Docker in one article

Preface

The project is going to use ElasticSearch. In order to avoid jamming in the later development, we have to start early. During the whole installation process, we encountered the following three problems.

• Docker installation is very slow
• ElasticSearch-Head connection appears cross-domain
• ElasticSearch-Head operation reports 406 error code

1. Install Docker

At present, Kaka’s understanding of Docker is only superficial. For things you don’t understand, you should use them more often. The more you use them, the more you will naturally master them.

Install the dependency package and execute the command yum install -y yum-utils device-mapper-persistent-data lvm2

If you directly execute the docker installation command at this time, you will find that it is very slow and the waiting process is long.

The problem can be solved by configuring the domestic source yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo The source used here is Alibaba Cloud.

Then execute the command yum install docker-ce docker-ce-cli containerd.io to install docker.

Configure systemctl enable docker enable docker

Execute systemctl start docker command to start Docker

Check the docker version to see if it is installed successfully

If there is a problem with the previous installation of docker, execute yum remove docker-ce to delete it and delete everything under /var/lib/docker .

WARNING: IPv4 forwarding is disabled. Networking will not work.

I searched Baidu with this error and found out that forwarding was not enabled. After the network bridge is configured, forwarding needs to be enabled.

If forwarding is not enabled, the above error will appear, indicating that there is no network.

Solution

Modify the configuration file /etc/sysctl.conf , add net.ipv4.ip_forward=1 , and then restart the service systemctl restart network for the configuration to take effect.

2. Install ElasticSearch

Use docker to directly obtain the es image and execute the command docker pull elasticsearch:7.7.0

After the execution is complete, execute docker images to see the image pulled in the previous step.

With the image, you can start creating containers. Next, create an es container.

Execute docker run --name elasticsearch -d -e ES_JAVA_OPTS="-Xms512m -Xmx512m" -e "discovery.type=single-node" -p 9200:9200 -p 9300:9300 elasticsearch:7.7.0

--name indicates the container name

-d: Run the container in the background and return the container ID;

-e: Specify the environment variables in the container

-p: specifies port mapping in the format of: host port: container port

After the command is executed, the container ID will be returned. Then execute docker ps -a to list all containers.

The default port of es is 9200. If you access it directly using only the IP address + port number, the following figure will be returned. The appearance of this interface indicates that your installation is successful.

At this point we have quickly installed ElasticSearch using Docker, and then we will install the client tools for ElasticSearch.

3. Install ElasticSearch-Head

Docker is also used for quick installation. As above, pull the image first and execute the command docker pull mobz/elasticsearch-head:5

Then create a container and execute docker create --name elasticsearch-head -p 9100:9100 mobz/elasticsearch-head:5

In order to ensure the clarity of the picture, the picture is not captured completely. This is also what Kaka will tell you next. Pay attention to the difference when creating the container twice.

When installing ElasticSearch, the container runs directly in the background after it is created successfully, but this is not consistent when installing ElasticSearch-Head.

Instead, specify the container name and port number and execute it directly. After the execution is completed, a container is created but not run.

That is, there is a box in the lower right corner of the picture above. You can see the status here and you will find that it is create.

So another operation is needed, which is to start the container docker start 容器id .

After the installation is complete, you can access it directly using域名plus port 9100 .

Handling cross-domain

When connecting to ElasticSearch, you will find that you cannot connect. Since the front-end and back-end are developed separately, there will be cross-domain problems, and cross-domain processing needs to be done on the server.

Execute the command docker exec -it elasticsearch /bin/bash to enter the ElasticSearch container created in the first step and modify the configuration file vi config/elasticsearch.yml .

http.cors.enabled: true
http.cors.allow-origin: "*"

Write the above two lines into the configuration file. Note that this is a yml configuration file. Here are some syntax details of this type of configuration file.

• There must be a space after the colon.
• Use spaces to indent the hierarchical relationship. Space data is not important, as long as there is a column of keys on the left.
• Very case sensitive
• Tabs are not allowed for indentation, only spaces are allowed.

After the configuration is modified, you need to execute the exit command to exit the container, and then execute docker restart 容器ID to restart the container.

Handling 406 Errors

At this point, you can successfully connect to ElasticSearch through ElasticSearch-Head , but a 406 error will be reported when performing data operations.

You only need to modify the configuration in the ElasticSearch-Head container and copy the configuration file to the host machine for modification.

Execute docker cp 容器ID:/usr/src/app/_site/vendor.js /usr/local/ . This command will copy the files in the docker container to your host directory.

Go to /usr/local and you can see the file vendor.js copied from the container.

Modify lines 6886 and 7574 of the file and change "application/x-www-from-urlencodes" to "application/json; charset=UTF-8"

After modification, copy the file to the container. The command to copy files from the container to the host has been used before, so now just reverse the two directories and execute docker cp /usr/local/vendor.js 容器ID:/usr/src/app/_site

The last step is重啟the ElasticSearch-Head container.

4. Install IK Tokenizer

First of all, let me ask a question, why do we need to use the IK word segmenter when ElasticSearch has its own word segmenter?

The word segmenter in ElasticSearch will divide Chinese characters into individual characters. For example, "Today is Friday" will be divided into "今", "天", "是", "周", and "五". This is obviously inappropriate. In most scenarios, words rather than characters are needed.

Therefore, you need to install the Chinese word segmenter IK to solve this problem.

IK provides two word segmentation algorithms: ik_smart and ik_max_word, where ik_smart is the least segmentation and ik_max_word is the most detailed. The differences between them will be presented to you in the next article.

It should be noted here that the installed version needs to be consistent with the ElasticSearch version.

Enter the ElasticSearch container docker exec -it 容器ID /bin/bash

Use wget to install, execute wget https://github.com/medcl/elasticsearch-analysis-ik/releases/download/v7.7.0/elasticsearch-analysis-ik-7.7.0.zip .

When you use wget to install and the message Unable to establish SSL connection appears, execute the following two commands.

yum install opensslls

yum install openssl-devel

Execute cd /usr/share/elasticsearch/plugins to go to the plugin directory and create an IK directory.

Move the compressed package to the IK directory and execute the decompression command elasticsearch-analysis-ik-7.7.0.zip

Then delete the compressed package. At this time, you can see a config package and several jar packages.

Finally, exit the container and restart the container.

V. Conclusion

In this article, everything you need to use ElasticSearch is ready. The next article will take you to use PHP's Laravel to encapsulate all ElasticSearch query methods.

Later, I will encapsulate a copy in Go and add some content to my own tool class.

This concludes this article about the process of installing ElasticSearch on Docker. For more information about installing ElasticSearch on Docker, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope you will support 123WORDPRESS.COM in the future!