一、简介
Redis是什么？redis是一款基于BSD协议，开源的非关系型数据库（nosql数据库），作者是意大利开发者Salvatore Sanfilippo在2009年发布，使用C语言编写；redis是基于内存存储，而且是目前比较流行的键值数据库（key-value database），它提供将内存通过网络远程共享的一种服务，提供类似功能的还有memcache，但相比 memcache，redis 还提供了易扩展、高性能、具备数据持久性等功能。主要的应用场景有session共享，常用于web集群中的tomcat或PHP中多web服务器的session共享；消息队列，ELK的日志缓存，部分业务的订阅发布系统；计数器，常用于访问排行榜，商品浏览数等和次数相关的数值统计场景；缓存，常用于数据查询、电商网站商品信息、新闻内容等；相对memcache，redis支持数据的持久化，可以将内存的数据保存在磁盘中，重启redis服务或者服务器之后可以从备份文件中恢复数据到内存继续使用；支持string（字符串）、hashes（关联数组）、list（列表）、set（集合）、sorted set（有序集合）、空间索引等数据结构的数据；支持数据的备份，可以实现类似于mysql中的主从模式的数据备份，支持使用快照和AOF（append only file）的数据持久化；支持比memcache更大的value数据，在memcache中只单个key value最大支持1MB，而redis最大支持512MB；Redis 是单线程，而 memcache 是多线程，所以单机情况下没有 memcache 并发高，但 redis 支持分布式集群以实现更高的并发，单 Redis 实例可以实现数万并发。除此以外，redis也支持集群横向扩展，基于redis cluster 的横向扩展，可以实现分布式集群，大幅度提升性能和数据安全；
二、redis安装
redis安装支持yum直接安装，前提是要配好epel源，该软件存放在epel仓库中；当然也可以下载源码直接编译安装，根据自己生产环境的需求，yum安装的版本稍微要旧一点，如果对应版本能够满足现有业务的需求，我个人觉得编译安装就没有必要；通常较新的程序在生产环境不建议使用；
1、yum安装
查看redis在epel源中的版本和简介
[root@node1 ~]# yum info redis
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Available Packages
Name : redis
Arch : x86_64
Version : 3.2.12
Release : 2.el7
Size : 544 k
Repo : epel/x86_64
Summary : A persistent key-value database
URL : http://redis.io
License : BSD
Description : Redis is an advanced key-value store. It is often referred to as a data
: structure server since keys can contain strings, hashes, lists, sets and
: sorted sets.
:
: You can run atomic operations on these types, like appending to a string;
: incrementing the value in a hash; pushing to a list; computing set
: intersection, union and difference; or getting the member with highest
: ranking in a sorted set.
:
: In order to achieve its outstanding performance, Redis works with an
: in-memory dataset. Depending on your use case, you can persist it either
: by dumping the dataset to disk every once in a while, or by appending
: each command to a log.
:
: Redis also supports trivial-to-setup master-slave replication, with very
: fast non-blocking first synchronization, auto-reconnection on net split
: and so forth.
:
: Other features include Transactions, Pub/Sub, Lua scripting, Keys with a
: limited time-to-live, and configuration settings to make Redis behave like
: a cache.
:
: You can use Redis from most programming languages also.
[root@node1 ~]#
提示：redis在epel中的版本是3.2.12，目前redis最新的版本是6.0.6，当然我们也可以去第三方网站找最新版本的rpm包，然后使用yum安装也行；
yum安装redis
[root@node1 ~]# yum install -y redis Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package redis.x86_64 0:3.2.12-2.el7 will be installed --> Processing Dependency: libjemalloc.so.1()(64bit) for package: redis-3.2.12-2.el7.x86_64 --> Running transaction check ---> Package jemalloc.x86_64 0:3.6.0-1.el7 will be installed --> Finished Dependency Resolution Dependencies Resolved ======================================================================================================================== Package Arch Version Repository Size ======================================================================================================================== Installing: redis x86_64 3.2.12-2.el7 epel 544 k Installing for dependencies: jemalloc x86_64 3.6.0-1.el7 epel 105 k Transaction Summary ======================================================================================================================== Install 1 Package (+1 Dependent package) Total download size: 648 k Installed size: 1.7 M Downloading packages: (1/2): jemalloc-3.6.0-1.el7.x86_64.rpm | 105 kB 00:00:00 (2/2): redis-3.2.12-2.el7.x86_64.rpm | 544 kB 00:00:00 ------------------------------------------------------------------------------------------------------------------------ Total 1.4 MB/s | 648 kB 00:00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : jemalloc-3.6.0-1.el7.x86_64 1/2 Installing : redis-3.2.12-2.el7.x86_64 2/2 Verifying : redis-3.2.12-2.el7.x86_64 1/2 Verifying : jemalloc-3.6.0-1.el7.x86_64 2/2 Installed: redis.x86_64 0:3.2.12-2.el7 Dependency Installed: jemalloc.x86_64 0:3.6.0-1.el7 Complete! [root@node1 ~]#
查看redis的程序环境
[root@node1 ~]# rpm -ql redis /etc/logrotate.d/redis /etc/redis-sentinel.conf /etc/redis.conf /etc/systemd/system/redis-sentinel.service.d /etc/systemd/system/redis-sentinel.service.d/limit.conf /etc/systemd/system/redis.service.d /etc/systemd/system/redis.service.d/limit.conf /usr/bin/redis-benchmark /usr/bin/redis-check-aof /usr/bin/redis-check-rdb /usr/bin/redis-cli /usr/bin/redis-sentinel /usr/bin/redis-server /usr/lib/systemd/system/redis-sentinel.service /usr/lib/systemd/system/redis.service /usr/libexec/redis-shutdown /usr/share/doc/redis-3.2.12 /usr/share/doc/redis-3.2.12/00-RELEASENOTES /usr/share/doc/redis-3.2.12/BUGS /usr/share/doc/redis-3.2.12/CONTRIBUTING /usr/share/doc/redis-3.2.12/MANIFESTO /usr/share/doc/redis-3.2.12/README.md /usr/share/licenses/redis-3.2.12 /usr/share/licenses/redis-3.2.12/COPYING /usr/share/man/man1/redis-benchmark.1.gz /usr/share/man/man1/redis-check-aof.1.gz /usr/share/man/man1/redis-check-rdb.1.gz /usr/share/man/man1/redis-cli.1.gz /usr/share/man/man1/redis-sentinel.1.gz /usr/share/man/man1/redis-server.1.gz /usr/share/man/man5/redis-sentinel.conf.5.gz /usr/share/man/man5/redis.conf.5.gz /var/lib/redis /var/log/redis /var/run/redis [root@node1 ~]#
提示：从上面命令返回的信息大概能够知道/etc/redis.conf是redis的配置文件，/usr/bin/redis-server是服务端程序，/usr/bin/redis-cli是客户端程序，/usr/lib/systemd/system/redis.service是redis的unit file服务管理脚本，/var/lib/redis是redis的数据目录；
启动redis
[root@node1 ~]# systemctl start redis [root@node1 ~]# ss -ntl State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 127.0.0.1:6379 *:* LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* [root@node1 ~]#
提示：redis默认监听在本机的127.0.0.1的6379端口，默认为了安全没有监听在其他地址，所以默认配置的redis不能够远程连接使用，必须修改配置文件中的监听地址才可以；
验证：用redis-cli连接redis server
提示：到此如果能够正常启动redis，能够用客户端连接到redis server 操作redis说明我们部署的redis服务就部署好了；
2、编译安装redis
准备源码包，和编译环境
[root@node2 yum.repos.d]# yum groupinstall "development tools" Loaded plugins: fastestmirror There is no installed groups file. Maybe run: yum groups mark convert (see man yum) extras | 2.9 kB 00:00:00 extras/7/x86_64/primary_db | 205 kB 00:00:00 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package autoconf.noarch 0:2.69-11.el7 will be installed --> Processing Dependency: m4 >= 1.4.14 for package: autoconf-2.69-11.el7.noarch ---> Package automake.noarch 0:1.13.4-3.el7 will be installed --> Processing Dependency: perl(Thread::Queue) for package: automake-1.13.4-3.el7.noarch --> Processing Dependency: perl(TAP::Parser) for package: automake-1.13.4-3.el7.noarch ……省略部分内容…… Installed: autoconf.noarch 0:2.69-11.el7 automake.noarch 0:1.13.4-3.el7 bison.x86_64 0:3.0.4-2.el7 byacc.x86_64 0:1.9.20130304-3.el7 cscope.x86_64 0:15.8-10.el7 ctags.x86_64 0:5.8-13.el7 diffstat.x86_64 0:1.57-4.el7 doxygen.x86_64 1:1.8.5-4.el7 elfutils.x86_64 0:0.176-4.el7 flex.x86_64 0:2.5.37-6.el7 gcc.x86_64 0:4.8.5-39.el7 gcc-c++.x86_64 0:4.8.5-39.el7 gcc-gfortran.x86_64 0:4.8.5-39.el7 indent.x86_64 0:2.2.11-13.el7 intltool.noarch 0:0.50.2-7.el7 libtool.x86_64 0:2.4.2-22.el7_3 patch.x86_64 0:2.7.1-12.el7_7 patchutils.x86_64 0:0.3.3-4.el7 rcs.x86_64 0:5.9.0-7.el7 redhat-rpm-config.noarch 0:9.1.0-88.el7.centos rpm-build.x86_64 0:4.11.3-43.el7 rpm-sign.x86_64 0:4.11.3-43.el7 subversion.x86_64 0:1.7.14-14.el7 swig.x86_64 0:2.0.10-5.el7 systemtap.x86_64 0:4.0-11.el7 Dependency Installed: apr.x86_64 0:1.4.8-5.el7 apr-util.x86_64 0:1.5.2-6.el7 avahi-libs.x86_64 0:0.6.31-20.el7 boost-date-time.x86_64 0:1.53.0-28.el7 boost-system.x86_64 0:1.53.0-28.el7 boost-thread.x86_64 0:1.53.0-28.el7 bzip2.x86_64 0:1.0.6-13.el7 cpp.x86_64 0:4.8.5-39.el7 dwz.x86_64 0:0.11-3.el7 dyninst.x86_64 0:9.3.1-3.el7 efivar-libs.x86_64 0:36-12.el7 emacs-filesystem.noarch 1:24.3-23.el7 gdb.x86_64 0:7.6.1-119.el7 gettext-common-devel.noarch 0:0.19.8.1-3.el7 gettext-devel.x86_64 0:0.19.8.1-3.el7 glibc-devel.x86_64 0:2.17-307.el7.1 glibc-headers.x86_64 0:2.17-307.el7.1 gnutls.x86_64 0:3.3.29-9.el7_6 json-c.x86_64 0:0.11-4.el7_0 kernel-debug-devel.x86_64 0:3.10.0-1127.13.1.el7 kernel-headers.x86_64 0:3.10.0-1127.13.1.el7 libdwarf.x86_64 0:20130207-4.el7 libgfortran.x86_64 0:4.8.5-39.el7 libmodman.x86_64 0:2.0.1-8.el7 libmpc.x86_64 0:1.0.1-3.el7 libproxy.x86_64 0:0.4.11-11.el7 libquadmath.x86_64 0:4.8.5-39.el7 libquadmath-devel.x86_64 0:4.8.5-39.el7 libstdc++-devel.x86_64 0:4.8.5-39.el7 m4.x86_64 0:1.4.16-10.el7 mokutil.x86_64 0:15-2.el7.centos mpfr.x86_64 0:3.1.1-4.el7 neon.x86_64 0:0.30.0-4.el7 nettle.x86_64 0:2.7.1-8.el7 pakchois.x86_64 0:0.4-10.el7 perl-Test-Harness.noarch 0:3.28-3.el7 perl-Thread-Queue.noarch 0:3.02-2.el7 perl-XML-Parser.x86_64 0:2.41-10.el7 perl-srpm-macros.noarch 0:1-8.el7 python-srpm-macros.noarch 0:3-32.el7 subversion-libs.x86_64 0:1.7.14-14.el7 systemtap-client.x86_64 0:4.0-11.el7 systemtap-devel.x86_64 0:4.0-11.el7 systemtap-runtime.x86_64 0:4.0-11.el7 trousers.x86_64 0:0.3.14-2.el7 unzip.x86_64 0:6.0-21.el7 zip.x86_64 0:3.0-11.el7 Dependency Updated: dbus.x86_64 1:1.10.24-14.el7_8 dbus-libs.x86_64 1:1.10.24-14.el7_8 elfutils-libelf.x86_64 0:0.176-4.el7 elfutils-libs.x86_64 0:0.176-4.el7 gettext.x86_64 0:0.19.8.1-3.el7 gettext-libs.x86_64 0:0.19.8.1-3.el7 glibc.x86_64 0:2.17-307.el7.1 glibc-common.x86_64 0:2.17-307.el7.1 libgcc.x86_64 0:4.8.5-39.el7 libgomp.x86_64 0:4.8.5-39.el7 libstdc++.x86_64 0:4.8.5-39.el7 rpm.x86_64 0:4.11.3-43.el7 rpm-build-libs.x86_64 0:4.11.3-43.el7 rpm-libs.x86_64 0:4.11.3-43.el7 rpm-python.x86_64 0:4.11.3-43.el7 Complete! [root@node2 yum.repos.d]#
提示：redis是C语言编写的，所以在Linux上编译C语言程序必须先安装gcc和一些常用的开发库；
下载源码包
解压源码包并进入到源码包解压目录
[root@node2 ~]# tar xf redis-6.0.6.tar.gz -C /usr/local/src/ tar: redis-6.0.6/.github/workflows/ci.yml: time stamp 2020-07-20 14:08:26 is 2772054.289890648 s in the future tar: redis-6.0.6/.github/workflows/daily.yml: time stamp 2020-07-20 14:08:26 is 2772054.289327433 s in the future tar: redis-6.0.6/.github/workflows: time stamp 2020-07-20 14:08:26 is 2772054.289233619 s in the future tar: redis-6.0.6/.github: time stamp 2020-07-20 14:08:26 is 2772054.289183193 s in the future tar: redis-6.0.6/.gitignore: time stamp 2020-07-20 14:08:26 is 2772054.289072272 s in the future tar: redis-6.0.6/00-RELEASENOTES: time stamp 2020-07-20 14:08:26 is 2772054.288536889 s in the future tar: redis-6.0.6/BUGS: time stamp 2020-07-20 14:08:26 is 2772054.288364759 s in the future tar: redis-6.0.6/CONTRIBUTING: time stamp 2020-07-20 14:08:26 is 2772054.287142408 s in the future ……省略部分内容…… [root@node2 ~]# cd /usr/local/src/ [root@node2 src]# ls redis-6.0.6 [root@node2 src]# cd redis-6.0.6/ [root@node2 redis-6.0.6]#
编译并安装redis到/usr/local/redis
提示：像这类错误，原因是centos上的gcc版本是4.8.5，版本过低导致的，解决办法就是装一个新版本的gcc（大于5.3）
升级gcc
[root@node2 redis-6.0.6]# yum install centos-release-scl Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package centos-release-scl.noarch 0:2-3.el7.centos will be installed --> Processing Dependency: centos-release-scl-rh for package: centos-release-scl-2-3.el7.centos.noarch --> Running transaction check ---> Package centos-release-scl-rh.noarch 0:2-3.el7.centos will be installed --> Finished Dependency Resolution Dependencies Resolved ======================================================================================================================== Package Arch Version Repository Size ======================================================================================================================== Installing: centos-release-scl noarch 2-3.el7.centos extras 12 k Installing for dependencies: centos-release-scl-rh noarch 2-3.el7.centos extras 12 k Transaction Summary ======================================================================================================================== Install 1 Package (+1 Dependent package) Total download size: 24 k Installed size: 39 k Is this ok [y/d/N]: y Downloading packages: (1/2): centos-release-scl-2-3.el7.centos.noarch.rpm | 12 kB 00:00:00 (2/2): centos-release-scl-rh-2-3.el7.centos.noarch.rpm | 12 kB 00:00:00 ------------------------------------------------------------------------------------------------------------------------ Total 83 kB/s | 24 kB 00:00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction Installing : centos-release-scl-rh-2-3.el7.centos.noarch 1/2 Installing : centos-release-scl-2-3.el7.centos.noarch 2/2 Verifying : centos-release-scl-2-3.el7.centos.noarch 1/2 Verifying : centos-release-scl-rh-2-3.el7.centos.noarch 2/2 Installed: centos-release-scl.noarch 0:2-3.el7.centos Dependency Installed: centos-release-scl-rh.noarch 0:2-3.el7.centos Complete! [root@node2 redis-6.0.6]#
提示：安装centos-release-scl主要是添加scl仓库地址文件到本地
[root@node2 redis-6.0.6]# yum install devtoolset-7-gcc* Loaded plugins: fastestmirror centos-sclo-rh | 3.0 kB 00:00:00 centos-sclo-sclo | 3.0 kB 00:00:00 (1/2): centos-sclo-sclo/x86_64/primary_db | 291 kB 00:00:00 (2/2): centos-sclo-rh/x86_64/primary_db | 2.9 MB 00:00:00 Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * centos-sclo-rh: mirrors.aliyun.com * centos-sclo-sclo: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check ---> Package devtoolset-7-gcc.x86_64 0:7.3.1-5.16.el7 will be installed --> Processing Dependency: devtoolset-7-binutils >= 2.22.52.0.1 for package: devtoolset-7-gcc-7.3.1-5.16.el7.x86_64 ……省略部分内容…… Installed: devtoolset-7-gcc.x86_64 0:7.3.1-5.16.el7 devtoolset-7-gcc-c++.x86_64 0:7.3.1-5.16.el7 devtoolset-7-gcc-gdb-plugin.x86_64 0:7.3.1-5.16.el7 devtoolset-7-gcc-gfortran.x86_64 0:7.3.1-5.16.el7 devtoolset-7-gcc-plugin-devel.x86_64 0:7.3.1-5.16.el7 Dependency Installed: audit-libs-python.x86_64 0:2.8.5-4.el7 checkpolicy.x86_64 0:2.5-8.el7 devtoolset-7-binutils.x86_64 0:2.28-11.el7 devtoolset-7-libquadmath-devel.x86_64 0:7.3.1-5.16.el7 devtoolset-7-libstdc++-devel.x86_64 0:7.3.1-5.16.el7 devtoolset-7-runtime.x86_64 0:7.1-4.el7 gmp-devel.x86_64 1:6.0.0-15.el7 libcgroup.x86_64 0:0.41-21.el7 libgfortran4.x86_64 0:8.3.1-2.1.1.el7 libmpc-devel.x86_64 0:1.0.1-3.el7 libsemanage-python.x86_64 0:2.5-14.el7 mpfr-devel.x86_64 0:3.1.1-4.el7 policycoreutils-python.x86_64 0:2.5-34.el7 python-IPy.noarch 0:0.75-6.el7 scl-utils.x86_64 0:20130529-19.el7 setools-libs.x86_64 0:3.3.8-4.el7 Dependency Updated: audit.x86_64 0:2.8.5-4.el7 audit-libs.x86_64 0:2.8.5-4.el7 libselinux.x86_64 0:2.5-15.el7 libselinux-python.x86_64 0:2.5-15.el7 libselinux-utils.x86_64 0:2.5-15.el7 libsemanage.x86_64 0:2.5-14.el7 libsepol.x86_64 0:2.5-10.el7 policycoreutils.x86_64 0:2.5-34.el7 Complete! [root@node2 redis-6.0.6]#
切换新版本的gcc
提示：这种方式是临时切换方式，如果需要永久切换，我们可以在/etc/profile文件中追加一条 souce /opt/rh/devtoolset-7/enable命令即可；
现在我们把gcc的版本切换到7.3.1，再来编译redis看看是否还会有错误发生？
[root@node2 redis-6.0.6]# make PREFIX=/usr/local/redis install
make: Warning: File `Makefile' has modification time 2768632 s in the future
cd src && make install
make[1]: Entering directory `/usr/local/src/redis-6.0.6/src'
make[1]: Warning: File `Makefile' has modification time 2768632 s in the future
CC adlist.o
CC quicklist.o
CC ae.o
CC anet.o
CC dict.o
CC server.o
CC sds.o
CC zmalloc.o
CC lzf_c.o
CC lzf_d.o
CC pqsort.o
CC zipmap.o
CC sha1.o
CC ziplist.o
CC release.o
CC networking.o
CC util.o
CC object.o
CC db.o
CC replication.o
CC rdb.o
CC t_string.o
CC t_list.o
CC t_set.o
CC t_zset.o
CC t_hash.o
CC config.o
CC aof.o
CC pubsub.o
CC multi.o
CC debug.o
CC sort.o
CC intset.o
CC syncio.o
CC cluster.o
CC crc16.o
CC endianconv.o
CC slowlog.o
CC scripting.o
CC bio.o
CC rio.o
CC rand.o
CC memtest.o
CC crcspeed.o
CC crc64.o
CC bitops.o
CC sentinel.o
CC notify.o
CC setproctitle.o
CC blocked.o
CC hyperloglog.o
CC latency.o
CC sparkline.o
CC redis-check-rdb.o
CC redis-check-aof.o
CC geo.o
CC lazyfree.o
CC module.o
CC evict.o
CC expire.o
CC geohash.o
CC geohash_helper.o
CC childinfo.o
CC defrag.o
CC siphash.o
CC rax.o
CC t_stream.o
CC listpack.o
CC localtime.o
CC lolwut.o
CC lolwut5.o
CC lolwut6.o
CC acl.o
CC gopher.o
CC tracking.o
CC connection.o
CC tls.o
CC sha256.o
CC timeout.o
CC setcpuaffinity.o
LINK redis-server
INSTALL redis-sentinel
CC redis-cli.o
LINK redis-cli
CC redis-benchmark.o
LINK redis-benchmark
INSTALL redis-check-rdb
INSTALL redis-check-aof
Hint: It's a good idea to run 'make test' ;)
INSTALL install
INSTALL install
INSTALL install
INSTALL install
INSTALL install
make[1]: warning: Clock skew detected. Your build may be incomplete.
make[1]: Leaving directory `/usr/local/src/redis-6.0.6/src'
make: warning: Clock skew detected. Your build may be incomplete.
[root@node2 redis-6.0.6]#
提示：切换gcc后，再次编译安装就没有报错了，到此redis编译安装就完成了；
查看编译安装好的redis目录结构
[root@node2 redis-6.0.6]# tree /usr/local/redis/
/usr/local/redis/
└── bin
├── redis-benchmark
├── redis-check-aof
├── redis-check-rdb
├── redis-cli
├── redis-sentinel -> redis-server
└── redis-server
1 directory, 6 files
[root@node2 redis-6.0.6]#
创建软连接到/usr/bin/
创建redis用户，并拷贝配置文件到redis安装目录
更改redis安装目录下的所有文件的属主和属组为redis
[root@node2 redis-6.0.6]# chown -R redis.redis /usr/local/redis/ [root@node2 redis-6.0.6]# ll /usr/local/redis/ total 0 drwxr-xr-x 2 redis redis 134 Jun 18 13:04 bin drwxr-xr-x 2 redis redis 24 Jun 18 13:18 etc [root@node2 redis-6.0.6]# ll /usr/local/redis/bin/ total 35700 -rwxr-xr-x 1 redis redis 4717872 Jun 18 13:04 redis-benchmark -rwxr-xr-x 1 redis redis 8952752 Jun 18 13:04 redis-check-aof -rwxr-xr-x 1 redis redis 8952752 Jun 18 13:04 redis-check-rdb -rwxr-xr-x 1 redis redis 4973312 Jun 18 13:04 redis-cli lrwxrwxrwx 1 redis redis 12 Jun 18 13:04 redis-sentinel -> redis-server -rwxr-xr-x 1 redis redis 8952752 Jun 18 13:04 redis-server [root@node2 redis-6.0.6]# ll /usr/local/redis/etc/ total 84 -rw-r--r-- 1 redis redis 83392 Jun 18 13:18 redis.conf [root@node2 redis-6.0.6]#
前台启动redis
提示：前台启动redis它给了我们三个警告，第一个是backlog设置的是511，但是/proc/sys/net/core/somaxconn设置的是128，需要更改；第二是是内核参数overcommit_memory设置的是0，如果设置成0在内核将检查是否有足够的可用内存供应用进程使用时，如果有足够的可用内存，内存申请允许，否则内存申请失败，并把错误返回给应用进程。这个内核参数有三个值0，1，2；其中1表示内核允许分配所有的物理内存，而不管当前的内存状态如何。2表示内核允许分配超过所有物理内存和交换空间总和的内存；第三个警告是内核开启了大页内存动态分配，需要关闭，让redis自己负责内存管理；
解决警告提示
提示：在centos7上/etc/rc.d/rc.local这个文件是没有执行权限的，这意味着我们在这个文件中写的开机启动命令是不会执行的，我们需要给它加上执行权限，在开机启动时里面写的开机启动命令才会被执行；在centos6上我们不需要给它加执行权限；
再次前台启动redis看看，看看是否还会有警告信息
验证6379端口是否启动，是否可以用redis-cli连接到redis-server上？
提示：可以看到重新开一个终端，能够看到6379端口监听在127.0.0.1这个地址上，并且我们使用redis-cli也可以正常连接到redis-server上正常操作；
给redis提供unit file让systemd来管理redis
提示：上面的ExecStart需要根据redis-server所在目录来指定
unit file
[Unit] Description=Redis persistent key-value database After=network.target After=network-online.target Wants=network-online.target [Service] ExecStart=/usr/local/redis/bin/redis-server /usr/local/redis/etc/redis.conf --supervised systemd ExecReload=/bin/kill -s HUP $MAINPID ExecStop=/bin/kill -s QUIT $MAINPID Type=forking User=redis Group=redis RuntimeDirectory=redis RuntimeDirectoryMode=0755 LimitNOFILE=65535 [Install] WantedBy=multi-user.target
修改配置文件让redis默认后台运行
验证：用systemctl命令来管理redis, 看看是否能够起停redis?
提示：可以看到用systemd可以正常的启动，重启，停止redis，设置redis开启启动，关闭开机启动，查看状态这些操作；