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This article mainly introduces the session management of Nginx Tomcat, which has certain reference value. Now I share it with you. Friends in need can refer to it
Nginx Tomcat has always understood the management of Session, but has never practiced it. This article starts from the simplest installation and startup, and gradually introduces several ways to manage sessions through examples.
[root@localhost ~]# yum install nginx
The prompt reports the following error:
No package nginx available.
Solution to install epel: EPEL EPEL is the abbreviation of Enterprise Linux Add-on Package. EPEL is created, maintained and managed by the Fedora Special Interest Group for Red Hat Enterprise Linux (RHEL) and its derivative distributions (such as CentOS, Scientific Linux, Oracle Enterprise Linux) A high-quality additional software package project;
[root@localhost ~]# yum install epel-release
After installation, you can successfully install nginx;
Enter the directory of nginx first
[root@localhost nginx]# cd /usr/sbin/
Execute command
./nginx 开启 ./nginx -s stop 使用kill命令强制杀掉进程 ./nginx -s quit 待nginx进程处理任务完毕进行停止 ./nginx -s reload
drwxr-xr-x. 9 root root 4096 May 7 14:16 apache-tomcat-7.0.88_8081 drwxr-xr-x. 9 root root 4096 May 7 14:16 apache-tomcat-7.0.88_8082
Modify the index.jsp of webapps/ROOT to facilitate testing
<%
if(request.getSession().getAttribute("key")==null){
out.println("key is null,ready init.....");
request.getSession().setAttribute("key","value");
}else{
out.println("key is not null,key="+request.getSession().getAttribute("key"));
}
%>
<br>
sessionID:<%=session.getId()%>
<br>
sessionCreateTime:<%= session.getCreationTime() %>
<br>
<%
out.println("tomcat port 8081");
%>
The final output specifies the respective port numbers 8081 and 8082 under the two tomcats
Modify nginx.conf under /etc/nginx/
upstream tomcatTest {
server 127.0.0.1:8081; #tomcat-8081
server 127.0.0.1:8082; #tomcat-8082
}
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name _;
root /usr/share/nginx/html;
# Load configuration files for the default server block.
include /etc/nginx/default.d/*.conf;
location / {
proxy_pass http://tomcatTest;
}
error_page 404 /404.html;
location = /40x.html {
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
}
}
The load balancing strategy configured here is the default polling strategy. nginx also supports other strategies including: ip_hash, weight , fair (third party), url_hash (third party);
Default policy Each web request is assigned to different back-end servers one by one in chronological order. In this case, a new session will be created for each request. Do the following Simple test:
First request http://ip/
key is null,ready init..... sessionID:E7A9782DED29FF04E21DF94078CB4F62 sessionCreateTime:1527732911441 tomcat port 8082
Second refresh http://ip/
key is null,ready init..... sessionID:7812E8E21DBB74CC7FBB75A0DFF2E9CB sessionCreateTime:1527732979810 tomcat port 8081
Third refresh http://ip/
key is null,ready init..... sessionID:8895F41E299785A21995D5F8BB734B86 sessionCreateTime:1527733011878 tomcat port 8082
It can be found that a new session is generated every time, and the messages are distributed to different back-end servers one by one in chronological order. Generally, websites that need to maintain sessions are not allowed to generate a session for each request. ;
Each request is allocated according to the hash result of the access IP, so that each visitor has a fixed access to a back-end server, which can solve the problem of session Question; nginx can achieve sticky Session by configuring ip_hash in the upstream module;
upstream tomcatTest {
ip_hash;
server 127.0.0.1:8081; #tomcat-8081
server 127.0.0.1:8082; #tomcat-8082
}
Do a simple test below:
The first request is http://ip/
key is null,ready init..... sessionID:859BADFB09A4ECEAEC5257F518C228A0 sessionCreateTime:1527734181450 tomcat port 8081
The second Refresh http://ip/
key is not null,key=value sessionID:859BADFB09A4ECEAEC5257F518C228A0 sessionCreateTime:1527734181450 tomcat port 8081
for the third time and refresh http://ip/
key is not null,key=value sessionID:859BADFB09A4ECEAEC5257F518C228A0 sessionCreateTime:1527734181450 tomcat port 8081
for the third time. You can find that key=value is set in the first request, and it can be obtained every time thereafter. To the key value, the sessionId has not changed, and tomcat has not changed, achieving a sticky Session;
At this time, you can stop tomcat with port=8081, and then observe
The fourth refresh of http://ip/
key is null,ready init..... sessionID:3C15FE2C8E8A9DCDC6EAD48180B78B80 sessionCreateTime:1527735994476 tomcat port 8082
The fifth time you refresh http://ip/
key is not null,key=value sessionID:3C15FE2C8E8A9DCDC6EAD48180B78B80 sessionCreateTime:1527735994476 tomcat port 8082
you can find that the message is forwarded to tomcat-8082, and the session is lost, and a new session is re-created;
How to make this In this case, the session is not lost, and there are two solutions: Session replication and Session sharing; Session sharing is better in terms of scalability and performance. The following focuses on how to implement Session sharing;
The idea of Session sharing is to save the session in a public place and then take it out when used. The specific public place can be: redis, db, memcached, etc., as follows redis is an instance
yum install redis
After the installation is complete, configure the file /etc/redis.conf
Start the redis server
redis-server /etc/redis.conf
Start the client
redis-cli
$TOMCAT_HOME/lib and adds the following jar package
<dependency> <groupId>com.bluejeans</groupId> <artifactId>tomcat-redis-session-manager</artifactId> <version>2.0.0</version> </dependency> <dependency> <groupId>redis.clients</groupId> <artifactId>jedis</artifactId> <version>2.5.2</version> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-pool2</artifactId> <version>2.2</version> </dependency>
Modify $TOMCAT_HOME/conf The context.xml file in the directory
<Valve className="com.orangefunction.tomcat.redissessions.RedisSessionHandlerValve" />
<Manager className="com.orangefunction.tomcat.redissessions.RedisSessionManager"
host="localhost"
port="6379"
database="0"
maxInactiveInterval="60"/>
Tomcat provides an open session management and persistence org.apache.catalina.session.ManagerBase. By inheriting this abstract class and making some simple configurations, you can Your session management class takes over Tomcat's session reading and persistence. Here, tomcat-redis-session-manager is used to manage the session;
RedisSessionManager inherits from the org.apache.catalina.session.ManagerBase class and is responsible for the session. Related operations are all in this category;
The first request is http://ip/
key is null,ready init..... sessionID:1131499E5A65DE1591152465E7B24B1F sessionCreateTime:1527740273682 tomcat port 8081
The second time is refreshing http://ip/
key is not null,key=value sessionID:1131499E5A65DE1591152465E7B24B1F sessionCreateTime:1527740273682 tomcat port 8081
Stop tomcat-8081 and refresh http://ip/
key is not null,key=value sessionID:1131499E5A65DE1591152465E7B24B1F sessionCreateTime:1527740273682 tomcat port 8082
for the third time. You can find that the message has been forwarded to the tomcat-8082 node, but the session has not changed. At the same time, the key can also get the value;
5. Check redis
[root@localhost ~]# redis-cli 127.0.0.1:6379> keys * 1) "1131499E5A65DE1591152465E7B24B1F" 127.0.0.1:6379> get 1131499E5A65DE1591152465E7B24B1F "\xac\xed\x00\x05sr\x00Dcom.orangefunction.tomcat.redissessions.SessionSerializationMetadataB\xd9\xd9\xf7v\xa2\xdbL\x03\x00\x01[\x00\x15sessionAttributesHasht\x00\x02[Bxpw\x14\x00\x00\x00\x10}\xc8\xc9\xcf\xf6\xc3\xb5Y\xc7\x0c\x8eF\xa5\xfaQ\xe8xsr\x00\x0ejava.lang.Long;\x8b\xe4\x90\xcc\x8f#\xdf\x02\x00\x01J\x00\x05valuexr\x00\x10java.lang.Number\x86\xac\x95\x1d\x0b\x94\xe0\x8b\x02\x00\x00xp\x00\x00\x01c\xb4j\x94\x12sq\x00~\x00\x03\x00\x00\x01c\xb4j\x94\x12sr\x00\x11java.lang.Integer\x12\xe2\xa0\xa4\xf7\x81\x878\x02\x00\x01I\x00\x05valuexq\x00~\x00\x04\x00\x00\a\bsr\x00\x11java.lang.Boolean\xcd r\x80\xd5\x9c\xfa\xee\x02\x00\x01Z\x00\x05valuexp\x01q\x00~\x00\nsq\x00~\x00\x03\x00\x00\x01c\xb4j\x94*t\x00 1131499E5A65DE1591152465E7B24B1Fsq\x00~\x00\a\x00\x00\x00\x01t\x00\x03keyt\x00\x05valuew\b\x00\x00\x01c\xb4j\x94\x12"
and you can find that the session object has been stored in redis, and the sessionId is used as the key value to store the binary data of the session;
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