The installation of a new version of Redis reports an error, as follows:
Current gcc version:
Upgrade gcc version:
yum -y install centos-release-scl
yum -y install devtoolset-9-gcc devtoolset-9-gcc-c++ devtoolset-9-binutils
scl enable devtoolset-9 bash
Install again using make
As shown below, the program reports an error when connecting to redis. According to the error information, redis is running in protected mode. It needs to be set under the redis command line: config set protected-mode no.
-DENIED Redis is running in protected mode because protected mode is enabled, no bind address was specified, no authentication password is requested to clients. In this mode connections are only accepted from the loopback interface. If you want to connect from external computers to Redis you may adopt one of the following solutions: Just disable protected mode sending the command ‘CONFIG SET protected-mode no’ from the loopback interface by connecting to Redis from the same host the server is running, however MAKE SURE Redis is not publicly accessible from internet if you do so. Use CONFIG REWRITE to make this change permanent. Alternatively you can just disable the protected mode by editing the Redis configuration file, and setting the protected mode option to ‘no’, and then restarting the server. If you started the server manually just for testing, restart it with the ‘–protected-mode no’ option. Setup a bind address or an authentication password. NOTE: You only need to do one of the above things in order for the server to start accepting connections from the outside.
Error message when using pycharm to connect to redis:
Detect redis port 6379 through telnet command
Solution:
Set protected-mode no
Check the redis port 6379 through the telnet command again, and there is no access exception.
Run Python again to connect to redis:
Supplementary knowledge:
When you use telnet (telnet IP port number) to connect to the host under Linux/Unix, you will be prompted “escape character is’ ^] ‘. What does this mean? How to solve it?
Escape character is ‘^]’. Solution
“^” means the Ctrl key!
1. This prompt means that pressing Ctrl +] will call out the command line of Telnet!
2. After the telnet command line comes out, you can execute the telnet command;
3. Exit the telnet command line with the name quit.
Common telnet commands
close closes the current connection
logout forces the remote user to exit and close the connection
display displays the parameters of the current operation
mode attempted to enter command line mode or character mode
open connect to a site
quit exit
telnetsend send special characters
set sets the parameters of the current operation
unset resets the current operating parameters
status print status information
toggle switch operation parameters
slc changes the state of special characters
Auth on/off confirmation function Z suspended
Telnetenviron changes the environment variable and displays help
To sum up, escape character is’ ^] ‘. It is just a prompt that you can call the command line of Telnet using Ctrl +] key.
An error occurred when redis was started under Windows Environment: could not create server TCP listening socket 127.0.0.1:6379: bind: the operation completed successfully.
Problem Description:
When redis is started in the windows environment today, an error is reported:
Solution:
① run command: redis-cli.exe
② Exit Redis
③ Run the command: redis-server.exe redis.windows.conf
Start successfully!
If you don’t change any configuration one day and somehow open the redis server to flash back, you can enter the redis-server directory in the command line and enter redis-server.exe redis.windows.conf command to view the error information
If an error is reported as follows
QForkMasterInit: system error caught. error code=0x000005af, message=VirtualAllocEx failed
It means that you have not set the maximum memory of redis
Open redis.windows.conf with Notepad
Add the code below to the last line.
maxmemory 268435456
maxheap 314572800
[resolved]
java.lang.IllegalAccessError: class org.springframework.data.redis.core.$ Proxy237 cannot access its superinterface org.springframework.data.redis.core.RedisConnectionUtils$RedisConnectionProxy
In the serviceImpl class operation redis reported the above error, after investigation found that the cause is in the (with write operation [@Transactional (readOnly = false)]) transaction method of operation redis, in the readOnly = true transaction method can be operated normally
ps: other versions of redis do not know if there is also this situation for the time being
solution: the operation of redis to get @Transactional (readOnly = false) method outside the operation can be
Problem Description.
SpringBoot integration with Redis annotations, requesting an error:
java.io.NotSerializableException: com.demo.entity.MemberEntity at
java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
~[na:1.8.0_191] at
java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
~[na:1.8.0_191] at
java.util.ArrayList.writeObject(ArrayList.java:766) ~[na:1.8.0_191]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
~[na:1.8.0_191] at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
~[na:1.8.0_191] at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
~[na:1.8.0_191] at java.lang.reflect.Method.invoke(Method.java:498)
~[na:1.8.0_191] at
java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:1140)
~[na:1.8.0_191] at
java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1496)
~[na:1.8.0_191] at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
~[na:1.8.0_191] at
java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
~[na:1.8.0_191] at
java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
~[na:1.8.0_191]
Problem: Serialization is not performed in the entity class
Solution: Serializable interface is implemented in the entity class
Problem Description.
Springboot integration redis annotations, request access with the following error:
org.springframework.expression.spel.SpelEvaluationException: EL1008E:
Property or field ‘getListMember’ cannot be found on object of type
‘org.springframework.cache.interceptor.CacheExpressionRootObject’ –
maybe not public or not valid?
Reason: missing single quotes in redis tag
Solution:
Add single quotes to the redis tag
Text
Service A restarts, zuul without adding a retry mechanism, and A service error exception will be reported
Solution: Modify gateway profile
hystrix:
command:
default:
execution:
isolation:
thread:
timeout-in-milliseconds: 20000
zuul:
host:
connect-timeout-millis: 20000
socket-timeout-millis: 20000
routes:
#userMicroservices
userService:
#All requests with /user as the header are forwarded to user
path: /user/**
serviceId: user
#url: http://localhost:8091
pickupService:
#All requests with /pickup as the header are forwarded to pickup
path: /pickup/**
serviceId: pickup
orderService:
#All requests with /order as the header are forwarded to order
path: /order/**
serviceId: order
#Whether retryable is enabled
retryable: true
ribbon:
#resolve the timeout problem caused by zuul forwarding requests
ReadTimeout: 60000
SocketTimeout: 60000
# of retries for the current service
MaxAutoRetries: 2
# of times to switch the same Server
MaxAutoRetriesNextServer: 0
1. Problems
When you use redis-server.exe to startup directly, it will flashback. When it is started with script and configuration file, it will also flashback. When it is started with command line, an error will be reported:
[23848] 16 Mar 16:10:32.565 # QForkMasterInit: system error caught. error code=0x000005af, message=VirtualAllocEx failed.: unknown error
2. Solutions
Redis’s conf file sets the parameters maxheap and maxmemory
maxmemory 120MB
maxheap 180MB
Maxmemory and maxheap depend on your computer configuration. Usually: maxheap = 1.5 * maxmemory
1. Log in to redis database
[ root@localhost ~]# redis-cli -h 192.168.1.19
2. View redis configuration information
192.168.1.19:6379> info
2. According the path of config_file to set dump.rdb file storage path, or you can customize the path
192.168.1.19:6379> config set dir /storage/redis/
3. Save and exit
192.168.1.19:6379> save
192.168.1.19:6379> exit
4. Restart redis service
[ root@localhost ~]# service redis stop
[ root@localhost ~]# service redis start
An error is reported when closing redis
(error) ERR Errors trying to SHUTDOWN. Check logs.First, we need to understand that when we shutdown, redis will save the data, whether it is rdb or aof depends on your own settings. But when you save the file, you may encounter the save path does not exist, or the save path does not have permission, in the configuration file, the default save path for rdb is . /. So we have a problem because of path permissions.
Modify . / file permissions
[atguigu@hadoop100 bin]$ sudo chown atguigu:atguigu -R /usr/local/bin/redis-config/Shut down again and stop successfully
Solve the redis client on error: error: write econnaborted config rightwe
Problem Description:
Solution:
1. First, check whether the firewall of Linux is turned on
Turn off the firewall
[root@localhost]# systemctl stop firewalld.service
Open 6379 port
[root@localhost]# sudo firewall-cmd --zone=public --add-port=6379/tcp --permanent
success
[root@localhost]# sudo firewall-cmd --reload
success
2. Check whether the redis startup configuration is correct
Check whether redis is started
ps -ef | grep redis
For versions above redis 3.2, Internet access is not allowed by default, and needs to be modified redis.conf configuration file
Modify peetected-mode
Modify peotected-mode yes
to: protected-mode no.
#The protected-mode parameter is used to disable access to redis from outside the network, if enabled, only the localhost ip (127.0.0.1) will be able to access Redis
Close bind 127.0.0.1
Comment out bind 127.0.0.1, or modify bind 0.0.0.0, to allow access to all ip addresses
After modifying the configuration file, remember to restart redis,
./redis-server /usr/local/redis/redis.conf