redis-cluster安装需要通过gem install redis来安装相关依赖。否则报错。
通过gem install redis会报如下错误1：
ERROR: Loading command: install (LoadError)
cannot load such file -- zlib
ERROR: While executing gem ... (NoMethodError)
undefined method `invoke_with_build_args' for nil:NilClass
这是缺少zlib依赖，需要安装zlib库
还有一个错误2就是
ERROR: While executing gem ... (Gem::Exception)
Unable to require openssl,install OpenSSL and rebuildruby(preferred)or use non-HTTPS sources
提示缺少openssl库，这两个库可以通过yum安装，但是安装了需要集成到ruby中。
先解决错误一，解决办法分为两步：
一、安装zlib库，如果已经安装，跳过，直接进入第二步。
yum install zlib-devel
二、集成zlib库到ruby环境
cd /data/ruby-2.4.2
cd ext/zlib
ruby extconf.rb
//在操作下一步之前需要修改Makefile文件中的zlib.o: $(top_srcdir)/include/ruby.h,将$(top_srcdir)修改为../.. 如下
//zlib.o: ../../include/ruby.h
//这一步如果不修改，make时会爆出另外一个错误
//make:*** No rule to make target `/include/ruby.h', needed by `zlib.o'. Stop
make && make install
另一个缺少openssl库的错误，可以用同样的问题解决。
一、安装openssl库，如果已经安装可以跳过，直接进入第二步。
yum install openssl-devel
不要只用yum install openssl来安装，否则会缺少pcre等相关库，执行ruby extconf.rb会提示找不到ssl.h文件。
checkingfort_open()in -lnsl... no
checkingforsocket()in -lsocket... no
checkingforopenssl/ssl.h... no
第二步、集成openssl库到ruby
cd /data/ruby-2.4.2
cd ext/openssl
ruby extconf.rb
//同样修改Makefile中的$(top_srcdir)为../..
make && make install
[root@node01 openssl]# make && make install
compiling openssl_missing.c
compiling ossl.c
compiling ossl_asn1.c
compiling ossl_bio.c
compiling ossl_bn.c
compiling ossl_cipher.c
compiling ossl_config.c
compiling ossl_digest.c
compiling ossl_engine.c
compiling ossl_hmac.c
compiling ossl_ns_spki.c
compiling ossl_ocsp.c
compiling ossl_pkcs12.c
compiling ossl_pkcs5.c
compiling ossl_pkcs7.c
compiling ossl_pkey.c
compiling ossl_pkey_dh.c
compiling ossl_pkey_dsa.c
compiling ossl_pkey_ec.c
compiling ossl_pkey_rsa.c
compiling ossl_rand.c
compiling ossl_ssl.c
compiling ossl_ssl_session.c
compiling ossl_x509.c
compiling ossl_x509attr.c
compiling ossl_x509cert.c
compiling ossl_x509crl.c
compiling ossl_x509ext.c
compiling ossl_x509name.c
compiling ossl_x509req.c
compiling ossl_x509revoked.c
compiling ossl_x509store.c
linking shared-object openssl.so
/usr/bin/install -c -m0755openssl.so /usr/local/lib/ruby/site_ruby/2.4.0/x86_64-linux
installingdefaultopenssl libraries
成功之后，再次运行gem install redis，出现以下界面：
Fetching: redis-4.0.1.gem (100%)
Successfully installed redis-4.0.1
Parsing documentationforredis-4.0.1
Installing ri documentationforredis-4.0.1
Done installing documentationforredisafter1seconds
1gem installed
gem install redis安装成功。
