Docker failed to remotely access 3306 after installing MySQL

In Alibaba cloud server , Installed docker, And after starting the container, install mysql8.0. Connect... In a container mysql Everything is all right , Next, you are ready to use the in this computer navicat visit mysql, The connection error was found 10038. And then began a difficult investigation journey ！

First attempt , Because of root Created by the user , Think it is a group problem , So a personal user was created , The result is still not connected , Think of your own installation 8.0 Version of , There may be new features , It is found that the encryption rules of the user password are different （ Specific encryption rules can be queried by yourself ）, Old version navicat Not necessarily for , So try to change the user's encryption rules to the old version , Connecting again still fails ！

        The following figure shows the process of modifying password rules .

View modified results ：

After modifying the rule still fails , I wonder if it's the port , So from this telnet ip port , Find out 22 It can be connected normally ,3306 no way , Thought it was the firewall , So the firewall is turned off , Still not .

Check the port started under ：

  The port information is found to be normal .

This makes me wonder , Then there is a saying in Baidu that Alibaba cloud will have a security policy configuration , Able to add port access settings for the portal , So I went to the Alibaba cloud console and added

  A new rule has been added to the security group rules

  Finally, the connection was successful ！

notes ：

        In fact, the security group policy was operated before the problem was solved , But it was useless at that time , I wonder if it could be mysql The version is too high , So it was removed 8.0 The container of , again pull 了 5.7 edition , As a result, it exploded , Because I used to pretend a long time ago docker, And what I tried was 5.7 edition , This causes the container to report an error ,run After starting, it is directly disabled . After several twists and turns , I haven't found a good way , You can only uninstall docker, Go through the new process again after reassembly .

        So when the uninstall is complete , install docker, The following is the official installation tutorial .Install Docker Engine on CentOS | Docker DocumentationInstructions for installing Docker Engine on CentOShttps://docs.docker.com/engine/install/centos/

After installation according to the en route steps ,pull 了 8.0 Version of mysql And start the , Then go to alicloud and add the configuration of the last step , Try using local navicat Connect , It was a success ..

Problem guess ：

1. Adopted mysql8.0 Mirror image , Then the external connection tool shall also adopt the new version as far as possible , For example, my local is navicat15 To connect . Previously used 11 Never . Some bloggers say that mysql5.7-8.0 Two versions , The user password is encrypted in different ways , The new password is not supported by the connection worker . I have also tried this process , The encryption method is rolled back , It's no use .

2. Firewall impact , This is influential , However, my Alibaba cloud server is not turned on at all . This doesn't affect me ..

3. docker Before installation of the container , Better make sure , Whether there is any installation record , In some cases, you need to clear all the old version records in advance , Uninstall and reinstall the existing installation , Avoid mirror conflicts .

4. Alibaba cloud's security policy really didn't expect .. After all, it is the operation and maintenance department that handles this matter , I seldom think about port opening . Fortunately, after tossing and turning, it was done .

The whole process took me about two nights , It's close 4 Hours! . Sure enough, I did it myself , Still have a good attitude , There are many places to step on the pit . then docker I haven't used it much , Not very familiar with , I hope we can make persistent efforts --