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  • 云计算概述和KVM虚拟化

    一、云计算概述
    为什么有书还需要培训;
    xftp;
    查找问题:之前干了什么?
    中国的计算机行业已经跨入了云计算行业;

    运维工资虚高;

    1、传统的数据中心面临的问题
    为什么分享的人做的非常好:a、想跳槽了;b、宣传的公司的产品; c、提高知名度;

    搞电脑的;
    a、云计算是一种使用模式;b、云计算是通过网络进行访问的;c、按需付费,弹性计算;
    包年包费:是vps;

    IDC托管
    IDC租用
    虚拟主机
    VPS openvz
    云主机
    

    有足够的机器的话,无需自动化扩容;
    但是如果对于机器资源不足的话,需要实现自动化的调度,可以使用自动化扩容;

    2、云计算和虚拟化

    IaaS:操作系统一下,不包含操作系统; Managed by vendor
    PaaS:操作系统,运行环境等;
    SaaS:软件即服务,应用,数据,全部包含;eg:邮箱(反垃圾,反垃圾邮件联盟);

    云计算和虚拟化不能比较:云计算是一种模式,虚拟化是一种技术;

    不知道虚拟机是干什么的?不知道干什么的?不敢停

    云计算是使用虚拟化的技术,来实现的;云计算是通过网络来获取资源的;

    虚拟化分类:

        1)、全虚拟化:KVM虚拟化是内核支持,CPU需要支持;
    	2)、半虚拟化:zone;
    
    	服务器虚拟化:
    	桌面虚拟化:
    	应用虚拟化:
    

    携程和京东使用的是基于openstack的桌面虚拟化;

    ESXI  XenServer
    KVM  RHEV   oVirt  openstack
    Vmware Vshpere
    EMC 被Dell收购了

    3、KVM虚拟化
    特性:

        1)嵌入的linux内核中
        2)代码级资源调用
        3)虚拟机就是一个进程;
    

    建议使用CentOS 7,目前所有的开源软件都是支持的;  

    二、KVM常用管理

    1、创建虚拟机

    [root@linux-node1 ~]# yum install qemu-kvm qemu-kvm qemu-kvm-tools virt-manager libvirt virt-install -y

    一台机器分为:cpu、内存、IO(磁盘、网络);
    kvm(是一个内核模块,是内核态的,需要用户态的程序进行管理)有:cpu和内存;
    qemu(本身是一个虚拟化软件,是用户态软件)有:磁盘和网络;

    kvm需要硬件虚拟化支持,查看硬件是否支持虚拟化:

    [root@linux-node3 ~]# grep -E '(vmx|svm)' /proc/cpuinfo
    flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq vmx ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx hypervisor lahf_lm ida arat epb pln pts dtherm hwp hwp_noitfy hwp_act_window hwp_epp tpr_shadow vnmi ept vpid xsaveopt xsavec xgetbv1

    默认虚拟机没有打开硬件虚拟化,需要在setting中进行设置;

    创建虚拟机的磁盘:

    	[root@linux-node1 ~]# qemu-img create -f raw /opt/CentOS-7.1-x86_64.raw 10G    #创建一个虚拟机,-f指定文件格式
    	Formatting '/opt/CentOS-7.1-x86_64.raw', fmt=raw size=10737418240
    
    	[root@linux-node1 opt]# lsmod |grep kvm
    	kvm_intel             162153  0 
    	kvm                   525259  1 kvm_intel
    

    启动libvirt:

    	[root@linux-node1 ~]# systemctl enable libvirtd.service
    	Created symlink from /etc/systemd/system/sockets.target.wants/virtlockd.socket to /usr/lib/systemd/system/virtlockd.socket.
    	[root@linux-node1 ~]# 
    	[root@linux-node1 ~]# systemctl start  libvirtd.service
    	[root@linux-node1 ~]# systemctl status libvirtd.service
    	● libvirtd.service - Virtualization daemon
    	   Loaded: loaded (/usr/lib/systemd/system/libvirtd.service; enabled; vendor preset: enabled)
    	   Active: active (running) since Thu 2017-02-09 15:11:11 CST; 3min 50s ago
    

      

    创建ISO镜像文件:

    dd  if=/dev/cdrom of=/opt/CentOS-7.1.iso   #创建ISO文件
    	[root@linux-node1 ~]# virt-install --name CentOS-7.1-x86_64 --virt-type kvm --ram 1024 --cdrom=/opt/CentOS-7.1.iso  --disk path=/opt/CentOS-7.1-x86_64.raw,bus=sata --network network=default --graphics vnc,listen=0.0.0.0 --noautoconsole
    
    	Starting install...
    	Creating domain...                                                                                                                                                            |    0 B  00:00:00     
    	Domain installation still in progress. You can reconnect to 
    	the console to complete the installation process.
    	
    

    如果使用virt-manager+xmanager安装的话,需要设置环境变量DISPLAY:

                export DISPLAY=192.168.74.1:0.0

    选择cdrom:

    我这里使用的使用virt-manager安装的,由于之前磁盘接口默认是ide的,总是包ide-0-0-0找不到的错误,安装失败,所以在安装的时候需要将磁盘接口选择为sata的;
    	使用vnc,默认监听端口为5900;

    远程连接选择vnc:

    在安装的时候,设置网卡名为eth0:

    	[root@linux-node3 ~]# ps aux|grep kvm    #kvm就是宿主机中的一个进程
    	root       610  0.0  0.0      0     0 ?        S<   06:38   0:00 [kvm-irqfd-clean]
    	qemu      4830  1.9 23.3 1730568 438344 ?      Sl   08:03   2:28 /usr/libexec/qemu-kvm -name CentOS-7.1-x86_64 -S -machine pc-i440fx-rhel7.0.0,accel=kvm,usb=off -cpu Westmere -m 1024 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid 6201bfeb-ae90-447d-b75a-1c09cbd7f658 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-8-CentOS-7.1-x86_64/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -global PIIX4_PM.disable_s3=1 -global PIIX4_PM.disable_s4=1 -boot strict=on -device ich9-usb-ehci1,id=usb,bus=pci.0,addr=0x6.0x7 -device ich9-usb-uhci1,masterbus=usb.0,firstport=0,bus=pci.0,multifunction=on,addr=0x6 -device ich9-usb-uhci2,masterbus=usb.0,firstport=2,bus=pci.0,addr=0x6.0x1 -device ich9-usb-uhci3,masterbus=usb.0,firstport=4,bus=pci.0,addr=0x6.0x2 -device ahci,id=sata0,bus=pci.0,addr=0x5 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x7 -drive file=/opt/CentOS-7.1-x86_64,format=raw,if=none,id=drive-virtio-disk0 -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive if=none,media=cdrom,id=drive-sata0-0-0,readonly=on -device ide-cd,bus=sata0.0,drive=drive-sata0-0-0,id=sata0-0-0 -netdev tap,fd=26,id=hostnet0,vhost=on,vhostfd=28 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:ae:02:78,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channel/target/domain-8-CentOS-7.1-x86_64/org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=org.qemu.guest_agent.0 -chardev spicevmc,id=charchannel1,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=com.redhat.spice.0 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 0.0.0.0:0 -k en-us -vga qxl -global qxl-vga.ram_size=67108864 -global qxl-vga.vram_size=67108864 -global qxl-vga.vgamem_mb=16 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=2 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=3 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x9 -msg timestamp=on
    	root      4854  0.0  0.0      0     0 ?        S    08:03   0:00 [kvm-pit/4830]
    	root      7059  0.0  0.0 112668   972 pts/2    R+   10:09   0:00 grep --color=auto kvm
    

    2、libvirt介绍

    支持xen,kvm,vmware,virtualbox等等;

    [root@linux-node3 ~]# virsh list   #libvirt api的工具
     Id    名称                         状态
    ----------------------------------------------------
     1     CentOS-7.1-x86_64              running
     2     CentOS-7.2-x86_64              running
    
    [root@linux-node3 ~]# virsh list --all
     Id    名称                         状态
    ----------------------------------------------------
     1     CentOS-7.1-x86_64              running
     2     CentOS-7.2-x86_64              running
    

    openstack默认使用kvm;

    libvirt会创建如下的网卡:

    		vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
    				inet6 fe80::fc54:ff:feae:278  prefixlen 64  scopeid 0x20<link>
    				ether fe:54:00:ae:02:78  txqueuelen 1000  (Ethernet)
    				RX packets 160  bytes 15462 (15.0 KiB)
    				RX errors 0  dropped 0  overruns 0  frame 0
    				TX packets 4271  bytes 227026 (221.7 KiB)
    				TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    

    在新创建的虚拟机上,编辑网卡,设为开机自启动,使用 ip ad li查看,网卡有地址,是因为dncp的原因:

    		[root@linux-node3 ~]# ps aux|grep dns
    		nobody    1519  0.0  0.0  15544   468 ?        S    06:38   0:00 /sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/libexec/libvirt_leaseshelper
    		root      1522  0.0  0.0  15516   164 ?        S    06:38   0:00 /sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/default.conf --leasefile-ro --dhcp-script=/usr/libexec/libvirt_leaseshelper
    		root      7662  0.0  0.0 112668   968 pts/2    S+   10:36   0:00 grep --color=auto dns
    

    可以看到分配的libvirt的地址的范围:

    		[root@linux-node3 ~]# cat /var/lib/libvirt/dnsmasq/default.conf    
    		##WARNING:  THIS IS AN AUTO-GENERATED FILE. CHANGES TO IT ARE LIKELY TO BE
    		##OVERWRITTEN AND LOST.  Changes to this configuration should be made using:
    		##    virsh net-edit default
    		## or other application using the libvirt API.
    		##
    		## dnsmasq conf file created by libvirt
    		strict-order
    		pid-file=/var/run/libvirt/network/default.pid
    		except-interface=lo
    		bind-dynamic
    		interface=virbr0
    		dhcp-range=192.168.122.2,192.168.122.254    #dncp分配的地址范围
    		dhcp-no-override
    		dhcp-lease-max=253
    		dhcp-hostsfile=/var/lib/libvirt/dnsmasq/default.hostsfile
    		addn-hosts=/var/lib/libvirt/dnsmasq/default.addnhosts
    

    3、CPU热添加

    virsh edit CentOS-7.1-x86_64    #编辑libvirt的xml文件  

    <vcpu placement='auto' current='1'>4</vcpu>   #cpu的热添加,最大为4个;cpu的热添加,只有在Centos 7才能做

    相当于直接编辑该文件:

    [root@linux-node3 qemu]# pwd
    /etc/libvirt/qemu
    [root@linux-node3 qemu]# ls
    CentOS-7.1-x86_64.xml  CentOS-7.2-x86_64.xml  networks
    

    编辑xml文件之后,只有重启虚拟机才能生效:

    		[root@linux-node3 ~]# virsh shutdown CentOS-7.1-x86_64    #编辑完xml之后,需要重启才能生效
    		域 CentOS-7.1-x86_64 被关闭
    		[root@linux-node3 ~]# virsh start CentOS-7.1-x86_64 
    		域 CentOS-7.1-x86_64 已开始
    

    将cpu的个数改为2个

    [root@linux-node3 ~]# virsh setvcpus CentOS-7.1-x86_64  2 --live
    

    然后再虚拟机上查看cat /proc/cpuinfo,可以看到cpu变成两个了

    查看CPU是否激活

    [root@linux-node3 ~]# cat /sys/devices/system/cpu/cpu0/online 
    1
    

    cpu的个数只能加,不能减少

    		[root@linux-node3 ~]# virsh setvcpus CentOS-7.1-x86_64  1 --live    #只能加,不能减
    		错误:不支持的配置:failed to find appropriate hotpluggable vcpus to reach the desired target vcpu count
    

    注意:#cpu热添加,不能超过cpu最大数;

    4、内存热添加

    <memory unit='KiB'>2048576</memory>    #内存的最大值,内存的变化,最大不能超过最大值;

    修改完成之后,需要重启虚拟机;

    		[root@linux-node3 ~]# virsh qemu-monitor-command --help
    		  NAME
    			qemu-monitor-command - QEMU 监控程序命令
    
    		  SYNOPSIS
    			qemu-monitor-command <domain> [--hmp] [--pretty] {[--cmd] <string>}...
    
    		  DESCRIPTION
    			QEMU 监控程序命令
    
    		  OPTIONS
    			[--domain] <string>  域名,id 或 uuid
    			--hmp            采用认同监控协议的命令
    			--pretty         以美化格式输出任意 qemu 监视器协议输出结果
    			[--cmd] <string>  命令
    		
    		
    		[root@linux-node3 ~]# virsh qemu-monitor-command CentOS-7.1-x86_64 --hmp --cmd info
    		info balloon  -- show balloon information
    		info block  -- show the block devices
    		info block-jobs  -- show progress of ongoing block device operations
    		info blockstats  -- show block device statistics
    		info capture  -- show capture information
    		info chardev  -- show the character devices
    		info cpus  -- show infos for each CPU
    		info history  -- show the command line history
    		info irq  -- show the interrupts statistics (if available)
    		info jit  -- show dynamic compiler info
    		info kvm  -- show KVM information
    		info mem  -- show the active virtual memory mappings
    		info mice  -- show which guest mouse is receiving events
    		info migrate  -- show migration status
    		info migrate_cache_size  -- show current migration xbzrle cache size
    		info migrate_capabilities  -- show current migration capabilities
    		info mtree  -- show memory tree
    		info name  -- show the current VM name
    		info network  -- show the network state
    		info numa  -- show NUMA information
    		info pci  -- show PCI info
    		info pcmcia  -- show guest PCMCIA status
    		info pic  -- show i8259 (PIC) state
    		info profile  -- show profiling information
    		info qdm  -- show qdev device model list
    		info qtree  -- show device tree
    		info registers  -- show the cpu registers
    		info roms  -- show roms
    		info snapshots  -- show the currently saved VM snapshots
    		info spice  -- show the spice server status
    		info status  -- show the current VM status (running|paused)
    		info tlb  -- show virtual to physical memory mappings
    		info tpm  -- show the TPM device
    		info trace-events  -- show available trace-events & their state
    		info usb  -- show guest USB devices
    		info usbhost  -- show host USB devices
    		info usernet  -- show user network stack connection states
    		info uuid  -- show the current VM UUID
    		info version  -- show the version of QEMU
    		info vnc  -- show the vnc server status
    

    设置虚拟机内存的大小,内存可大可小

    	[root@linux-node3 ~]# virsh qemu-monitor-command CentOS-7.1-x86_64 --hmp --cmd balloon 600   #内存设置为600M
    
    
    	[root@linux-node3 ~]# virsh qemu-monitor-command CentOS-7.1-x86_64 --hmp --cmd info balloon 
    	balloon: actual=600
    
    
    	[root@linux-node3 ~]# virsh qemu-monitor-command CentOS-7.1-x86_64 --hmp --cmd balloon 2000    #设为2G
    	 
    
    	[root@linux-node3 ~]# virsh qemu-monitor-command CentOS-7.1-x86_64 --hmp --cmd info balloon 
    	balloon: actual=2000
    

     

    5、硬盘

    	全镜像模式				稀疏模式
    	raw 					qcow2(openstack首选)
    

    查看硬盘的信息

    	[root@linux-node3 opt]# ll
    	总用量 14763012
    	-rw-r--r--. 1 qemu qemu  4379901952 2月  12 00:03 CentOS-7.1.iso
    	-rw-------. 1 qemu qemu 10737418240 2月  12 15:06 CentOS-7.1-x86_64
    	drwxr-xr-x. 2 root root           6 3月  26 2015 rh
    	[root@linux-node3 opt]# qemu-img info CentOS-7.1-x86_64
    	image: CentOS-7.1-x86_64
    	file format: raw
    	virtual size: 10G (10737418240 bytes)
    	disk size: 10G
    

      

    6、网络

    默认是nat

    如何将nat该为桥接模式?

    查看网桥

    [root@linux-node3 ~]# brctl show
    bridge name     bridge id               STP enabled     interfaces
    virbr0          8000.5254003ca721       yes             virbr0-nic
                                                            vnet0
                                                            vnet1
    

     

    添加网桥,并将eth0关联进去 

    	[root@linux-node3 ~]# brctl addbr br0    #添加一个网桥
    	[root@linux-node3 ~]# brctl show
    	bridge name     bridge id               STP enabled     interfaces
    	br0             8000.000000000000       no
    	virbr0          8000.5254003ca721       yes             virbr0-nic
    															vnet0
    															
    	[root@linux-node3 ~]# brctl addif br0 eth0    #将eth0加进去(网断了)
    

      

    删除eth0的ip地址,加入到br0中

    ,就可以重启连接了

    [root@linux-node3 ~]# brctl show
    bridge name     bridge id               STP enabled     interfaces
    br0             8000.000c29385f8a       no              eth0
    virbr0          8000.5254003ca721       yes             virbr0-nic
                                                            vnet0
                                                            vnet1
    

    这样,网卡就实现桥接了

    [root@linux-node3 ~]# ifconfig 
    br0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 192.168.74.22  netmask 255.255.255.0  broadcast 192.168.74.255
            inet6 fe80::20c:29ff:fe38:5f8a  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:38:5f:8a  txqueuelen 1000  (Ethernet)
            RX packets 105  bytes 15245 (14.8 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 80  bytes 11974 (11.6 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet6 fe80::38c2:5066:2880:ac5f  prefixlen 64  scopeid 0x20<link>
            ether 00:0c:29:38:5f:8a  txqueuelen 1000  (Ethernet)
            RX packets 323111  bytes 35975466 (34.3 MiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 304017  bytes 436428151 (416.2 MiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
            inet 127.0.0.1  netmask 255.0.0.0
            inet6 ::1  prefixlen 128  scopeid 0x10<host>
            loop  txqueuelen 1  (Local Loopback)
            RX packets 130  bytes 13769 (13.4 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 130  bytes 13769 (13.4 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    virbr0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
            ether 52:54:00:3c:a7:21  txqueuelen 1000  (Ethernet)
            RX packets 538  bytes 36160 (35.3 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 411  bytes 35200 (34.3 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    vnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet6 fe80::fc54:ff:feae:278  prefixlen 64  scopeid 0x20<link>
            ether fe:54:00:ae:02:78  txqueuelen 1000  (Ethernet)
            RX packets 523  bytes 41742 (40.7 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 8501  bytes 456432 (445.7 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    
    vnet1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
            inet6 fe80::fc54:ff:feaa:3c07  prefixlen 64  scopeid 0x20<link>
            ether fe:54:00:aa:3c:07  txqueuelen 1000  (Ethernet)
            RX packets 15  bytes 1950 (1.9 KiB)
            RX errors 0  dropped 0  overruns 0  frame 0
            TX packets 819  bytes 43640 (42.6 KiB)
            TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
    

      

    7、删除虚拟机

    		virsh undefine CentOS-7.1-x86_64   #删除就找不到了,可以先将xml备份
    		
    		[root@linux-node3 ~]# virsh suspend CentOS-7.1-x86_64     #挂起
    		域 CentOS-7.1-x86_64 被挂起
    
    		[root@linux-node3 ~]# virsh list
    		 Id    名称                         状态
    		----------------------------------------------------
    		 13    CentOS-7.1-x86_64              暂停
    
    		[root@linux-node3 ~]# virsh  resume CentOS-7.1-x86_64    #恢复
    		域 CentOS-7.1-x86_64 被重新恢复
    
    		[root@linux-node3 ~]# virsh list
    		 Id    名称                         状态
    		----------------------------------------------------
    		 13    CentOS-7.1-x86_64              running
    

    三、kvm性能优化

    1、CPU优化

    cpu是qume模拟的;
    x86有四个运行级别:rang0~ring3
    ring0是内核态(可以使用硬件),ring3是用户态(不可以使用硬件);
    如果进程需要使用硬件,进程需要切换到ring0上,这样的切换称之为上下文切换;
    只实现了ring0和ring3;

    vt-x:上下文切换技术实现;

    查看CPU状态

    	[root@linux-node3 /]# lscpu     #查看cpu状态
    	Architecture:          x86_64
    	CPU op-mode(s):        32-bit, 64-bit
    	Byte Order:            Little Endian
    	CPU(s):                1
    	On-line CPU(s) list:   0
    	Thread(s) per core:    1
    	Core(s) per socket:    1
    	座:                 1
    	NUMA 节点:         1
    	厂商 ID:           GenuineIntel
    	CPU 系列:          6
    	型号:              78
    	型号名称:        Intel(R) Core(TM) i5-6200U CPU @ 2.30GHz
    	步进:              3
    	CPU MHz:             2400.000
    	BogoMIPS:            4800.01
    	虚拟化:           VT-x
    	超管理器厂商:  VMware
    	虚拟化类型:     完全
    	L1d 缓存:          32K  #一级数据缓存
    	L1i 缓存:          32K   #一级指令缓存
    	L2 缓存:           256K
    	L3 缓存:           3072K
    	NUMA 节点0 CPU:    0
    

      

    减少Cache Miss

    		xml
    		taskset:将某一个进程绑定到某一个CPU上;
    

      

    内存优化

    	内存寻址:EPT
    	内存合并:KSM
    	大页内存:khugepaged 把连续的4k内存合并为2M;
    	
    	1、宿主机虚拟内存-->宿主机物理内存
    	影子页表:
    	虚拟机的虚拟内存->虚拟机的物理内存
    	
    	[root@linux-node3 /]# cat /sys/kernel/mm/transparent_hugepage/enabled 
    	[always] madvise never
    

      

    I/O

      一般内核优化很少做,内核裁剪可以做;

      Virtio(虚拟化的队列接口)  virtio-net  virtio-blk 半虚拟化  io半虚拟化

      linux的IO调度算法: 

    		cfq:完全公平的io调度算法;
    		fifo:用于SSD;
    

    查看IO调度算法 

    	[root@linux-node3 /]# dmesg |grep -i scheduler
    	[    1.264325] io scheduler noop registered
    	[    1.264327] io scheduler deadline registered (default)
    	[    1.264344] io scheduler cfq registered
    

      

    修改IO调度算法

    	[root@linux-node3 /]# cat /sys/block/sda/queue/scheduler 
    	noop [deadline] cfq 
    	[root@linux-node3 /]# echo cfq >/sys/block/sda/queue/scheduler    #修改IO调度算法,如果要永久生效,需要修改内核参数
    	[root@linux-node3 /]# cat /sys/block/sda/queue/scheduler 
    	noop deadline [cfq] 
         elevator=noop #修改内核参数

      

    四、ovirt(RHEV的开源版本)和总结:

    	1.镜像制作:
    		分区的时候,只分一个/分区
    		不建议使用交换分区
    	2.删除虚拟机网卡的UUID MAC
    	3.安装基础软件包 net-tools lrzsz screen tree vim wget
    

    KVM管理平台:

    	openstack     cloudstack  cloud.com公司-->Ctrix -->Apache基金会-->Java
    	openNebula
    	oVirt:RHEV的开源版本;
    

    ovirt:管理端+客户端组成

    						oVirt Egine 	oVirt主机/节点
    						Vcenter   		Exsi
    

      

    开源的邮箱: 

    	iRedmail  
    	extmail  
    	Zimbra(开源版本)
    	现在:腾讯企业邮箱;
    	
    	
    	zstack
    	
    	SEU:搜索引擎优化;
    

      

    作业:

    	1.ovirt体验
    	2.openstack环境准备
    		CentOS7.1系统两台。每台2G内存
    		linux-node1.oldboy.com
    		linux-node2.oldboy.com
    	3.硬盘50G
    	4.Tightvnc view vnc客户端
    	5.SOA   消息队列   RestAPI	分布式存储和对象存储
    

    Dubbo:阿里开源的SOA框架,目前京东,当当都在使用,是基于RPC,zookeeper做注册中心;

    总结:

    	服务器虚拟化
    	桌面虚拟化
    	应用虚拟化
    	硬件虚拟化:Intel vt-x/EPT  AMD  AMD-v/PVI
    

      

      

      

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  • 原文地址:https://www.cnblogs.com/cqq-20151202/p/6371267.html
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