Tag Archives: Linux

[Solved] Linux Start solr Error: Your Max Processes Limit is currently 31202. It should be set to 65000 to avoid operational disruption.

Execute the startup specification after entering the bin directory

./solr start

report errors

What should I do?

View system limits

 ulimit -a

Now you need to change the system limit and log in to the root account

Locate the file/etc/security/limits At the end of conf, add the following two lines [added by default in some systems]

* soft nofile 65535
* hard nofile 65535

Then locate the file/etc/security/limits d/20-nproc.conf

Change 4096 to 65535

Login again and take effect after modification

nginx Server Start Error: nginx: [emerg] open() “/var/run/nginx/nginx.pid” failed (Linux Restart)


After Linux restarts, an error is reported when starting the nginx server


1. Use the command CD/usr/local/nginx/conf to enter the specified directory

2. Use the command VI nginx Conf modify the configuration file # and remove the # number in the figure

3. Change to PID/usr/local/nginx/logs/nginx.pid;

4. Use the command MKDIR/usr/local/nginx/logs to create a directory

5. Start nginx service

Linux Files Save Error: E325: ATTENTION [How to Solve]

Error Messages:

Found a swap file by the name “.server.properties.swp”
owned by: root dated: Thu Jan 1 12:02:39 2022
file name: /server.properties
modified: YES
user name: root host name: wang.localdomain
process ID: 10718 (still running)
While opening file “server.properties”
dated: Thu Jan 1  12:02:39 2022
(1) Another program may be editing the same file. If this is the case,
be careful not to end up with two different instances of the same
file when making changes. Quit, or continue with caution.
(2) An edit session for this file crashed.
Error: If this is the case, use “:recover” or “vim -r server.properties”
to recover the changes (see “:help recovery”).
Error: If you did this already, delete the swap file “.server.properties.swp”
to avoid this message.



First use (individual tutorials have said that the deleted files are in the root directory, at least I didn’t find them)
ls -a
to see if there is a .swp file that opens with an error
For example, the one I opened with an error was server.properties
In this file directory use ls -a

Then use rm -f

Then the error report disappears.

Linux format System Disk error [How to Solve]


When the hard disk has a system, the format prompt indicates that the system cannot format

Input: mkfs ext4 /dev/nvme0n1

Error reporting:/dev/nvme0n1 is appropriate in use by the system; will not make a filesystem here!


Prompt that/dev/sdk1 is in use/ Dev/sdk1 is being managed by DM, so when we create the file system, we will be prompted with an error. We can manually remove it to create the file system normally. The operation is as follows:

dmsetup status

dmsetup remove_all

dmsetup status

Execute the command: mkfs.ext4 /dev/nvme0n1

Linux Vsftp error: TP folder error [How to Solve]

[FTP solution] vsftpd (FTP server) problem of windows accessing Ubuntu 200 switching to ASCII mode, 227 entering passive mode (0,0,0

Question: as follows,

FTP folder error
an error occurred while opening the folder on the FTP server. Check that you have permission to access the folder.

200 switching to ASCII mode
227 Entering Passive Mode (0,0,0,0,227,175).


A rather bullshit approach

Operating under Windows:

Open network and sharing center and find Internet Options -> [advanced] this page,

Cancel “use passive FTP (compatible with firewall and DSL modem)”

[Solved] Linux starts MySQL service Error: Error code = exited, status = 127


The error reported when starting MySQL service is as follows:

[[email protected] mysql]# systemctl status mysqld
● mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Wed 2021-10-12 09:13:18 UTC; 4s ago
  Process: 1015 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=127)
  Process: 1991 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)

Oct 12 09:13:17 linmo systemd[1]: mysqld.service: control process exited, code=exited status=127
Oct 12 09:13:17 linmo systemd[1]: Failed to start MySQL Server.
Oct 12 09:13:17 linmo systemd[1]: Unit mysqld.service entered failed state.
Oct 12 09:13:17 linmo systemd[1]: mysqld.service failed.
Oct 12 09:13:18 linmo systemd[1]: mysqld.service holdoff time over, scheduling restart.
Oct 12 09:13:18 linmo systemd[1]: start request repeated too quickly for mysqld.service
Oct 12 09:13:18 linmo systemd[1]: Failed to start MySQL Server.
Oct 12 09:13:18 linmo systemd[1]: Unit mysqld.service entered failed state.
Oct 12 09:13:18 linmo systemd[1]: mysqld.service failed.
[[email protected] mysql]#


The system lacks dependent packages: libaio, numactl;


Install missing dependent packages: libaio, numactl

# install libaio
yum install libaio
# install numactl
#wget wget http://mirror.centos.org/centos-7/7/os/x86_64/Packages/numactl-libs-2.0.9-5.el7_1.x86_64.rpm
# installl numactl
rpm -ivh numactl-libs-2.0.9-5.el7_1.x86_64.rpm
# install perl
yum isntall perl


[Solved] linux Error: springboot org.springframework.context.ApplicationContextException: Failed to start bean ‘webServerStartStop’

org.springframework.context.ApplicationContextException: Failed to start bean 'webServerStartStop'; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:181) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.context.support.DefaultLifecycleProcessor.access$200(DefaultLifecycleProcessor.java:54) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start(DefaultLifecycleProcessor.java:356) ~[spring-context-5.3.13.jar!/:5.3.13] at java.lang.Iterable.forEach(Iterable.java:75) ~[na:1.8.0_171] at org.springframework.context.support.DefaultLifecycleProcessor.startBeans(DefaultLifecycleProcessor.java:155) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.context.support.DefaultLifecycleProcessor.onRefresh(DefaultLifecycleProcessor.java:123) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:935) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:586) ~[spring-context-5.3.13.jar!/:5.3.13] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145) ~[spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:765) [spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:445) [spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) [spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1354) [spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343) [spring-boot-2.5.7.jar!/:2.5.7] at com.pn.boot.MybatisLogApplication.main(MybatisLogApplication.java:12) [classes!/:0.0.1-SNAPSHOT] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_171] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_171] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_171] at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_171] at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:49) [3-boot-mybatis-log-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT] at org.springframework.boot.loader.Launcher.launch(Launcher.java:108) [3-boot-mybatis-log-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT] at org.springframework.boot.loader.Launcher.launch(Launcher.java:58) [3-boot-mybatis-log-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT] at org.springframework.boot.loader.JarLauncher.main(JarLauncher.java:88) [3-boot-mybatis-log-0.0.1-SNAPSHOT.jar:0.0.1-SNAPSHOT] Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat server at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:229) ~[spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.web.servlet.context.WebServerStartStopLifecycle.start(WebServerStartStopLifecycle.java:43) ~[spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.context.support.DefaultLifecycleProcessor.doStart(DefaultLifecycleProcessor.java:178) ~[spring-context-5.3.13.jar!/:5.3.13] ... 22 common frames omitted Caused by: java.lang.IllegalArgumentException: standardService.connector.startFailed at org.apache.catalina.core.StandardService.addConnector(StandardService.java:238) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer.java:282) ~[spring-boot-2.5.7.jar!/:2.5.7] at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:213) ~[spring-boot-2.5.7.jar!/:2.5.7] ... 24 common frames omitted Caused by: org.apache.catalina.LifecycleException: Protocol handler start failed at org.apache.catalina.connector.Connector.startInternal(Connector.java:1075) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.catalina.core.StandardService.addConnector(StandardService.java:234) ~[tomcat-embed-core-9.0.55.jar!/:na] ... 26 common frames omitted Caused by: java.net.BindException: 地址已在使用 at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_171] at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_171] at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_171] at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_171] at org.apache.tomcat.util.net.NioEndpoint.initServerSocket(NioEndpoint.java:271) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:226) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.tomcat.util.net.AbstractEndpoint.bindWithCleanup(AbstractEndpoint.java:1213) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1299) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:614) ~[tomcat-embed-core-9.0.55.jar!/:na] at org.apache.catalina.connector.Connector.startInternal(Connector.java:1072) ~[tomcat-embed-core-9.0.55.jar!/:na] ... 28 common frames omitted

The reason for Linux tomcat port occupancy is to close all the tomcats that are enabled in Linux.

[Solved] Deploying Tomcat connection in Linux Navicat reports error 2059 – authentication plugin ‘caching_sha2_Password ‘cannot be loaded: + Xi input 9 g

This problem gives me a headache because navicat15.0.26 does not support the newly added encryption method of mysql8.0, caching_sha2_Password, so we need to modify the user’s encryption method. First log in to MySQL,

mysql -uroot -p

This is my configuration information

Mysql 8.0.27
Navicat 15.0.26
tomcat 9.0.54

View encryption method:

show variables like 'default_authentication_plugin';

Log in to the database using the command-line client tool provided with MySQL database, and enter use mysql

Query the original authentication plug-in of MySQL user from the database user table

select user,host,plugin,authentication_string from user;

Replace the authentication plug-in used by the user with MySQL used in the previous version_ native_ password

ALTER USER 'root'@'localhost'IDENTIFIED WITH mysql_native_password BY'root';

Just use Navicat to connect again.

[Solved] Linux Start solr Server Error: Your open file limit is currently 1024

1. In the Linux system, when installing applications such as elastic search and Solr, the Linux system will prompt various installation failures due to various restrictions. Here are some problems encountered.

2. Various restrictions
1. View all system restrictions
ulimit – A

2. Modify the limit on the number of open files

***[WARN]***Your open file limit is currently 1024. It should be set to65000 to avoid operational disruption.


a) Switch to the root account first (note that the operation is unsuccessful if it is not switched)
b) modify the/etc/security/limits.conf file as root and add
* hard nofile 65000
* soft nofile 65000 at the end

3. Modify the opening process limit

***[WARN]***Your Max Processes Limit is currently 2048.It should be set to 65000 to avoid operational disruption.


a) Switch to the root account first (note that the operation is unsuccessful if it is not switched)
b) modify the/etc/security/limits.conf file as root and add it at the end

* hard nproc 65000
* soft nproc 65000