在CentOS 7上搭建Docker环境
Preface
We commonly use VMware or VirtualBox to install our Virtual Machines before.For the sake of creating a simple testing environment with less resources.I consider to implement a MySQL db server relies on docker which can help you saving your time when developing code or something else.
Introduce
What's docker?There're two concept you should first try to understand,image & container(like an iso file,put all kinds of different tools in it,then manage the by containner).You're supposed to package your applications(or indispensable software in your dev environment) to a container.Whenever you need a second evironment to install same softwares or dependent packages,only one thing that you migrate the image to it is neccessary.It's rather simple and efficient by using docker.
Procedure
Let's install docker and then implement a MySQL server on it,here we go.
1 ###Create a docker host named "docker" by vagrant.### 2 $ vagrant up docker 3 Bringing machine 'docker' up with 'virtualbox' provider... 4 ==> docker: Importing base box 'CentOS7'... 5 Progress: 30% 6 ==> docker: Matching MAC address for NAT networking... 7 ==> docker: Setting the name of the VM: Vagrant_docker_1529333111553_95525 8 ==> docker: Clearing any previously set forwarded ports... 9 ==> docker: Clearing any previously set network interfaces... 10 ==> docker: Preparing network interfaces based on configuration... 11 docker: Adapter 1: nat 12 docker: Adapter 2: hostonly 13 ==> docker: Forwarding ports... 14 docker: 22 (guest) => 2222 (host) (adapter 1) 15 ==> docker: Running 'pre-boot' VM customizations... 16 ==> docker: Booting VM... 17 ==> docker: Waiting for machine to boot. This may take a few minutes... 18 docker: SSH address: 127.0.0.1:2222 19 docker: SSH username: vagrant 20 docker: SSH auth method: private key 21 docker: 22 docker: Vagrant insecure key detected. Vagrant will automatically replace 23 docker: this with a newly generated keypair for better security. 24 docker: 25 docker: Inserting generated public key within guest... 26 docker: Removing insecure key from the guest if it's present... 27 docker: Key inserted! Disconnecting and reconnecting using new SSH key... 28 ==> docker: Machine booted and ready! 29 ==> docker: Checking for guest additions in VM... 30 docker: The guest additions on this VM do not match the installed version of 31 docker: VirtualBox! In most cases this is fine, but in rare cases it can 32 docker: prevent things such as shared folders from working properly. If you see 33 docker: shared folder errors, please make sure the guest additions within the 34 docker: virtual machine match the version of VirtualBox you have installed on 35 docker: your host and reload your VM. 36 docker: 37 docker: Guest Additions Version: 4.3.28 38 docker: VirtualBox Version: 5.1 39 ==> docker: Setting hostname... 40 ==> docker: Configuring and enabling network interfaces... 41 docker: SSH address: 127.0.0.1:2222 42 docker: SSH username: vagrant 43 docker: SSH auth method: private key 44 ==> docker: Mounting shared folders... 45 docker: /vagrant => E:/Vagrant 46 47 [root@docker ~]# yum install -y yum-utils device-mapper-persistent-data lvm2 48 -- Omitted. 49 50 Installed: 51 yum-utils.noarch 0:1.1.31-45.el7 52 53 Dependency Installed: 54 libxml2-python.x86_64 0:2.9.1-6.el7_2.3 python-chardet.noarch 0:2.2.1-1.el7_1 python-kitchen.noarch 0:1.1.1-5.el7 55 56 Updated: 57 device-mapper-persistent-data.x86_64 0:0.7.3-3.el7 lvm2.x86_64 7:2.02.177-4.el7 58 59 Dependency Updated: 60 device-mapper.x86_64 7:1.02.146-4.el7 device-mapper-event.x86_64 7:1.02.146-4.el7 device-mapper-event-libs.x86_64 7:1.02.146-4.el7 61 device-mapper-libs.x86_64 7:1.02.146-4.el7 libxml2.x86_64 0:2.9.1-6.el7_2.3 lvm2-libs.x86_64 7:2.02.177-4.el7 62 python-urlgrabber.noarch 0:3.10-8.el7 rpm.x86_64 0:4.11.3-32.el7 rpm-build-libs.x86_64 0:4.11.3-32.el7 63 rpm-libs.x86_64 0:4.11.3-32.el7 rpm-python.x86_64 0:4.11.3-32.el7 yum.noarch 0:3.4.3-158.el7.centos 64 65 ###Add repo of docker of aliyun.### 66 [root@docker ~]# yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo 67 Loaded plugins: fastestmirror 68 adding repo from: http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo 69 grabbing file http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo 70 repo saved to /etc/yum.repos.d/docker-ce.repo 71 [root@docker ~]# 72 73 ###Create metadata cache.### 74 [root@docker ~]# yum makecache fast 75 Loaded plugins: fastestmirror 76 base | 3.6 kB 00:00:00 77 docker-ce-stable | 2.9 kB 00:00:00 78 extras | 3.4 kB 00:00:00 79 updates | 3.4 kB 00:00:00 80 docker-ce-stable/x86_64/primary_db | 13 kB 00:00:00 81 Loading mirror speeds from cached hostfile 82 * base: mirrors.shu.edu.cn 83 * extras: ftp.sjtu.edu.cn 84 * updates: mirrors.shu.edu.cn 85 Metadata Cache Created 86 87 ###Install docker from repo.### 88 [root@docker ~]# yum -y install docker-ce 89 Loaded plugins: fastestmirror 90 Loading mirror speeds from cached hostfile 91 * base: mirrors.shu.edu.cn 92 * extras: ftp.sjtu.edu.cn 93 * updates: mirrors.shu.edu.cn 94 Resolving Dependencies 95 --> Running transaction check 96 ---> Package device-mapper-persistent-data.x86_64 0:0.4.1-2.el7 will be updated 97 ---> Package device-mapper-persistent-data.x86_64 0:0.7.3-3.el7 will be an update 98 ---> Package lvm2.x86_64 7:2.02.115-3.el7 will be updated 99 ---> Package lvm2.x86_64 7:2.02.177-4.el7 will be an update 100 --> Processing Dependency: lvm2-libs = 7:2.02.177-4.el7 for package: 7:lvm2-2.02.177-4.el7.x86_64 101 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_97)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 102 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_141)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 103 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_138)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 104 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_135)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 105 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_133)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 106 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_128)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 107 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_113)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 108 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_110)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 109 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_107)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 110 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_104)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 111 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_103)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 112 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_101)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 113 --> Processing Dependency: libdevmapper.so.1.02(DM_1_02_100)(64bit) for package: 7:lvm2-2.02.177-4.el7.x86_64 114 ---> Package yum-utils.noarch 0:1.1.31-45.el7 will be installed 115 116 -- Omitted. 117 118 Installed: 119 docker-ce.x86_64 0:18.03.1.ce-1.el7.centos -- The lastest version of docker CE is 18.03.1 120 121 Dependency Installed: 122 audit-libs-python.x86_64 0:2.8.1-3.el7 checkpolicy.x86_64 0:2.5-6.el7 container-selinux.noarch 2:2.55-1.el7 123 libcgroup.x86_64 0:0.41-15.el7 libseccomp.x86_64 0:2.3.1-3.el7 libsemanage-python.x86_64 0:2.5-11.el7 124 libtool-ltdl.x86_64 0:2.4.2-22.el7_3 lz4.x86_64 0:1.7.5-2.el7 pigz.x86_64 0:2.3.3-1.el7.centos 125 policycoreutils-python.x86_64 0:2.5-22.el7 python-IPy.noarch 0:0.75-6.el7 setools-libs.x86_64 0:3.3.8-2.el7 126 127 Updated: 128 centos-release.x86_64 0:7-5.1804.el7.centos.2 dracut.x86_64 0:033-535.el7 initscripts.x86_64 0:9.49.41-1.el7 129 130 Dependency Updated: 131 audit.x86_64 0:2.8.1-3.el7 audit-libs.x86_64 0:2.8.1-3.el7 dracut-config-rescue.x86_64 0:033-535.el7 132 dracut-network.x86_64 0:033-535.el7 glib2.x86_64 0:2.54.2-2.el7 kmod.x86_64 0:20-21.el7 133 libgudev1.x86_64 0:219-57.el7 libselinux.x86_64 0:2.5-12.el7 libselinux-devel.x86_64 0:2.5-12.el7 134 libselinux-python.x86_64 0:2.5-12.el7 libselinux-ruby.x86_64 0:2.5-12.el7 libselinux-utils.x86_64 0:2.5-12.el7 135 libsemanage.x86_64 0:2.5-11.el7 libsepol.x86_64 0:2.5-8.1.el7 libsepol-devel.x86_64 0:2.5-8.1.el7 136 policycoreutils.x86_64 0:2.5-22.el7 selinux-policy.noarch 0:3.13.1-192.el7_5.3 selinux-policy-targeted.noarch 0:3.13.1-192.el7_5.3 137 systemd.x86_64 0:219-57.el7 systemd-libs.x86_64 0:219-57.el7 systemd-sysv.x86_64 0:219-57.el7 138 139 Complete! 140 141 ###Check docker detail version.### 142 [root@docker ~]# docker version 143 Client: 144 Version: 18.03.1-ce 145 API version: 1.37 146 Go version: go1.9.5 147 Git commit: 9ee9f40 148 Built: Thu Apr 26 07:20:16 2018 149 OS/Arch: linux/amd64 150 Experimental: false 151 Orchestrator: swarm 152 Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running? 153 [root@docker ~]# 154 155 ###Create a docker daemon config file.### 156 [root@docker docker]# pwd 157 /etc/docker 158 [root@docker docker]# vim daemon.json 159 [root@docker docker]# cat daemon.json 160 { 161 "registry-mirrors": [ "https://registry.docker-cn.com"] 162 } 163 164 ###Start docker service and list infomations.### 165 [root@docker docker]# systemctl start docker 166 [root@docker docker]# docker info 167 Containers: 0 168 Running: 0 169 Paused: 0 170 Stopped: 0 171 Images: 0 172 Server Version: 18.03.1-ce 173 Storage Driver: devicemapper 174 Pool Name: docker-253:0-16777839-pool 175 Pool Blocksize: 65.54kB 176 Base Device Size: 10.74GB 177 Backing Filesystem: xfs 178 Udev Sync Supported: true 179 Data file: /dev/loop0 180 Metadata file: /dev/loop1 181 Data loop file: /var/lib/docker/devicemapper/devicemapper/data 182 Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata 183 Data Space Used: 11.8MB 184 Data Space Total: 107.4GB 185 Data Space Available: 7.6GB 186 Metadata Space Used: 581.6kB 187 Metadata Space Total: 2.147GB 188 Metadata Space Available: 2.147GB 189 Thin Pool Minimum Free Space: 10.74GB 190 Deferred Removal Enabled: true 191 Deferred Deletion Enabled: true 192 Deferred Deleted Device Count: 0 193 Library Version: 1.02.146-RHEL7 (2018-01-22) 194 Logging Driver: json-file 195 Cgroup Driver: cgroupfs 196 Plugins: 197 Volume: local 198 Network: bridge host macvlan null overlay 199 Log: awslogs fluentd gcplogs gelf journald json-file logentries splunk syslog 200 Swarm: inactive 201 Runtimes: runc 202 Default Runtime: runc 203 Init Binary: docker-init 204 containerd version: 773c489c9c1b21a6d78b5c538cd395416ec50f88 205 runc version: 4fc53a81fb7c994640722ac585fa9ca548971871 206 init version: 949e6fa 207 Security Options: 208 seccomp 209 Profile: default 210 Kernel Version: 3.10.0-229.el7.x86_64 211 Operating System: CentOS Linux 7 (Core) 212 OSType: linux 213 Architecture: x86_64 214 CPUs: 1 215 Total Memory: 993.6MiB 216 Name: docker 217 ID: 4GY3:Q2FL:P4DD:HOFN:WFJZ:RDAV:GMJA:RDFF:VTAS:VW6D:TSC6:LCSC 218 Docker Root Dir: /var/lib/docker 219 Debug Mode (client): false 220 Debug Mode (server): false 221 Registry: https://index.docker.io/v1/ 222 Labels: 223 Experimental: false 224 Insecure Registries: 225 127.0.0.0/8 226 Registry Mirrors: 227 https://registry.docker-cn.com/ 228 Live Restore Enabled: false 229 230 WARNING: devicemapper: usage of loopback devices is strongly discouraged for production use. 231 Use `--storage-opt dm.thinpooldev` to specify a custom block storage device. 232 WARNING: bridge-nf-call-iptables is disabled 233 WARNING: bridge-nf-call-ip6tables is disabled 234 235 ###Load image of CentOS7.### 236 [root@docker docker]# docker image 237 238 Usage: docker image COMMAND 239 240 Manage images 241 242 Options: 243 244 245 Commands: 246 build Build an image from a Dockerfile 247 history Show the history of an image 248 import Import the contents from a tarball to create a filesystem image 249 inspect Display detailed information on one or more images 250 load Load an image from a tar archive or STDIN 251 ls List images 252 prune Remove unused images 253 pull Pull an image or a repository from a registry 254 push Push an image or a repository to a registry 255 rm Remove one or more images 256 save Save one or more images to a tar archive (streamed to STDOUT by default) 257 tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE 258 259 Run 'docker image COMMAND --help' for more information on a command. 260 [root@docker docker]# docker images 261 REPOSITORY TAG IMAGE ID CREATED SIZE 262 [root@docker docker]# cd /vagrant 263 [root@docker vagrant]# ls -l 264 total 1887022 265 -rwxrwxrwx 1 vagrant vagrant 498180608 Mar 13 16:19 centos-7.0-x86_64.box 266 -rwxrwxrwx 1 vagrant vagrant 15080 Mar 21 18:42 epel-release-latest-7.noarch.rpm 267 drwxrwxrwx 1 vagrant vagrant 4096 Mar 18 16:42 masterha 268 -rwxrwxrwx 1 vagrant vagrant 87119 Nov 7 2014 mha4mysql-manager-0.56-0.el6.noarch.rpm 269 -rwxrwxrwx 1 vagrant vagrant 113914 Nov 7 2014 mha4mysql-manager-0.56.tar.gz 270 -rwxrwxrwx 1 vagrant vagrant 118521 Mar 11 18:36 mha4mysql-manager-0.57.tar.gz 271 -rwxrwxrwx 1 vagrant vagrant 36326 Nov 7 2014 mha4mysql-node-0.56-0.el6.noarch.rpm 272 -rwxrwxrwx 1 vagrant vagrant 50172 Nov 4 2014 mha4mysql-node-0.56.tar.gz 273 -rwxrwxrwx 1 vagrant vagrant 54484 Mar 11 18:36 mha4mysql-node-0.57.tar.gz 274 drwxrwxrwx 1 vagrant vagrant 4096 Jun 2 16:23 MyFlash-master 275 -rwxrwxrwx 1 vagrant vagrant 2339403 Jun 1 16:15 MyFlash-master.zip 276 drwxrwxrwx 1 vagrant vagrant 8192 May 3 17:22 MySQL 277 -rwxrwxrwx 1 vagrant vagrant 641798603 Mar 18 14:32 mysql-5.7.21-linux-glibc2.12-x86_64.tar.gz 278 drwxrwxrwx 1 vagrant vagrant 4096 Jun 8 15:57 mysqlbinlog_flashback-master 279 -rwxrwxrwx 1 vagrant vagrant 299829 Jun 8 15:41 mysqlbinlog_flashback-master.zip 280 -rwxrwxrwx 1 vagrant vagrant 4720640 Jun 8 16:57 pip-10.0.1.tar 281 -rwxrwxrwx 1 vagrant vagrant 74297 Jun 8 17:06 PyMySQL-0.8.1.tar.gz 282 -rwxrwxrwx 1 vagrant vagrant 59238400 Jun 8 16:17 Python-2.6.9.tar 283 drwxrwxrwx 1 vagrant vagrant 4096 Jun 8 17:18 setuptools-39.2.0 284 -rwxrwxrwx 1 vagrant vagrant 851112 Jun 8 17:17 setuptools-39.2.0.zip 285 -rwxrwxrwx 1 vagrant vagrant 4140 Jun 18 16:43 Vagrantfile 286 -rwxrwxrwx 1 vagrant vagrant 540672 Apr 19 14:21 zabbix-3.0.16.tar.gz 287 -rwxrwxrwx 1 vagrant vagrant 723758592 Jun 13 17:08 zst_centos7-201806.tar 288 [root@docker vagrant]# docker image load < zst_centos7-201806.tar 289 129b697f70e9: Loading layer [==================================================>] 205.1MB/205.1MB 290 e17a43dfd99e: Loading layer [==================================================>] 20.09MB/20.09MB 291 81230abc4426: Loading layer [==================================================>] 2.802MB/2.802MB 292 a70f1502766b: Loading layer [==================================================>] 3.584kB/3.584kB 293 4c4dfc844006: Loading layer [==================================================>] 6.656kB/6.656kB 294 49fde8c22696: Loading layer [==================================================>] 6.144kB/6.144kB 295 3fe67ade2cc6: Loading layer [==================================================>] 3.072kB/3.072kB 296 eeb315c508b1: Loading layer [==================================================>] 77.82kB/77.82kB 297 0439f8e04051: Loading layer [==================================================>] 8.704kB/8.704kB 298 ec476b61f06f: Loading layer [==================================================>] 13.82kB/13.82kB 299 9f752899cdce: Loading layer [==================================================>] 5.632kB/5.632kB 300 027f1ff8b124: Loading layer [==================================================>] 3.584kB/3.584kB 301 f9b50836c42f: Loading layer [==================================================>] 5.12kB/5.12kB 302 2f68f3a1869a: Loading layer [==================================================>] 89.6kB/89.6kB 303 61f05bc1691a: Loading layer [==================================================>] 495.2MB/495.2MB 304 24d441f4dab8: Loading layer [==================================================>] 191.5kB/191.5kB 305 Loaded image ID: sha256:7d0b68af5a06e04c2713dab89a293dc1b1dff5ccbaab8235e97cbc9cff7db2cb 306 [root@docker vagrant]# docker images 307 REPOSITORY TAG IMAGE ID CREATED SIZE 308 <none> <none> 7d0b68af5a06 5 days ago 694MB 309 310 ###Add a tag for repository.### 311 [root@docker vagrant]# docker tag 7d0b68af5a06 CentOS7 312 Error parsing reference: "CentOS7" is not a valid repository/tag: invalid reference format: repository name must be lowercase 313 [root@docker vagrant]# docker tag 7d0b68af5a06 centos7 - Change the repository name into lowercase. 314 [root@docker vagrant]# docker images 315 REPOSITORY TAG IMAGE ID CREATED SIZE 316 centos7 latest 7d0b68af5a06 6 days ago 694MB 317 [root@docker vagrant]# 318 319 ###Check whether there're running containers.### 320 [root@docker vagrant]# docker ps -a 321 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 322 [root@docker vagrant]# 323 324 ###Start a container with dependency of directory themselves.### 325 [root@docker vagrant]# mkdir mysql_soft 326 [root@docker vagrant]# mkdir data1 327 [root@docker vagrant]# docker run -d -v /vagrant/mysql_soft:/opt/mysql -v /vagrant/data1:/data -v /etc/hosts:/etc/hosts -p2222:22 --cap-add=NET_ADMIN --name node1 -h docker centos7 328 9ff260da9643d7b8243668699760d7a64d3f797a1cd2a9bc2562f11e9790dcc7 329 [root@docker vagrant]# df -h 330 Filesystem Size Used Avail Use% Mounted on 331 /dev/mapper/centos-root 8.4G 2.1G 6.3G 26% / 332 devtmpfs 488M 0 488M 0% /dev 333 tmpfs 497M 0 497M 0% /dev/shm 334 tmpfs 497M 6.7M 491M 2% /run 335 tmpfs 497M 0 497M 0% /sys/fs/cgroup 336 /dev/sda1 497M 118M 379M 24% /boot 337 none 612G 243G 369G 40% /vagrant 338 tmpfs 100M 0 100M 0% /run/user/0 339 /dev/dm-3 10G 682M 9.4G 7% /var/lib/docker/devicemapper/mnt/fe5e6b5cf3f15ebcd2a1d0805919d1858b789b37a2f5d1c31af771072e812334 340 shm 64M 0 64M 0% /var/lib/docker/containers/9ff260da9643d7b8243668699760d7a64d3f797a1cd2a9bc2562f11e9790dcc7/mounts/shm 341 [root@docker vagrant]# docker ps -a 342 CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 343 9ff260da9643 centos7 "/usr/bin/supervisor…" 14 seconds ago Up 13 seconds (healthy) 0.0.0.0:2222->22/tcp node1 344 345 ###Check the IP of docker "node1".### 346 [root@docker vagrant]# docker inspect node1 | grep IPAddress 347 "SecondaryIPAddresses": null, 348 "IPAddress": "172.17.0.2", 349 "IPAddress": "172.17.0.2", 350 351 ###Login docker "node1".### 352 [root@docker vagrant]# ssh root@172.17.0.2 353 The authenticity of host '172.17.0.2 (172.17.0.2)' can't be established. 354 ECDSA key fingerprint is 1c:3a:48:00:26:63:1f:5b:6d:82:bf:0a:4d:df:03:cc. 355 Are you sure you want to continue connecting (yes/no)? yes 356 Warning: Permanently added '172.17.0.2' (ECDSA) to the list of known hosts. 357 root@172.17.0.2's password: 358 Last login: Wed Jun 13 00:18:11 2018 from 172.17.0.1 359 [root@docker ~]# df -h 360 Filesystem Size Used Avail Use% Mounted on 361 /dev/mapper/docker-253:0-16777839-fe5e6b5cf3f15ebcd2a1d0805919d1858b789b37a2f5d1c31af771072e812334 10G 682M 9.4G 7% / 362 tmpfs 64M 0 64M 0% /dev 363 tmpfs 497M 0 497M 0% /sys/fs/cgroup 364 none 612G 243G 369G 40% /data 365 /dev/mapper/centos-root 8.4G 2.1G 6.3G 26% /etc/hosts 366 shm 64M 0 64M 0% /dev/shm 367 tmpfs 497M 0 497M 0% /proc/scsi 368 tmpfs 497M 0 497M 0% /sys/firmware
Summary
- The docker has been installed properly.Now all the newly added container can share the contents and diskspace in directory "/vagrant" on host "docker".
- You don't need to to copy MySQL db software to each of your node anymore now.
- As soon as you copy a file to "/vagrant",it will appear in the container's dierctory "/opt/mysql" and the free diskspace depends on your diskspace of physical machine.Does it convenient?I'm afraid it really does.
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博客地址： http://www.cnblogs.com/aaron8219 & http://blog.csdn.net/aaron8219
博客地址： http://www.cnblogs.com/aaron8219 & http://blog.csdn.net/aaron8219
