centos8环境判断当前操作系统是否虚拟机或容器

一，阿里云ECS的centos环境

1,执行systemd-detect-virt

[root@yjweb ~]# systemd-detect-virt
kvm

说明阿里云的ecs是在一个kvm环境中运行

2,看dmidecode的system信息也行

[root@yjweb ~]# dmidecode -t system
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.8 present.

Handle 0x0100, DMI type 1, 27 bytes
System Information
        Manufacturer: Alibaba Cloud
        Product Name: Alibaba Cloud ECS
        Version: pc-i440fx-2.1
        Serial Number: f5df2afa-62a5-4c7b-89e5-0791e3ba8c92
        UUID: f5df2afa-62a5-4c7b-89e5-0791e3ba8c92
        Wake-up Type: Power Switch
        SKU Number: Not Specified
        Family: Not Specified

Handle 0x2000, DMI type 32, 11 bytes
System Boot Information
        Status: No errors detected

系统信息中的 Alibaba Cloud ECS 能看出机器是阿里云的机器

3，查看此ecs的centos版本

[root@yjweb ~]# cat /etc/redhat-release
CentOS Linux release 8.0.1905 (Core)

说明：刘宏缔的架构森林是一个专注架构的博客，地址：https://www.cnblogs.com/architectforest

         对应的源码可以访问这里获取： https://github.com/liuhongdi/

 说明：作者:刘宏缔 邮箱: 371125307@qq.com

二，vmware fusion下的虚拟机

1,执行systemd-detect-virt 

[root@localhost weblc]# systemd-detect-virt 
vmware

2,看dmidecode的system信息

[root@localhost weblc]# dmidecode -t system
# dmidecode 3.1
Getting SMBIOS data from sysfs.
SMBIOS 2.7 present.

Handle 0x0001, DMI type 1, 27 bytes
System Information
        Manufacturer: VMware, Inc.
        Product Name: VMware Virtual Platform
        Version: None
        Serial Number: VMware-56 4d f8 f6 6c b3 ad f1-ff d5 80 97 fd ce 82 d4
        UUID: F6F84D56-B36C-F1AD-FFD5-8097FDCE82D4
        Wake-up Type: Power Switch
        SKU Number: Not Specified
        Family: Not Specified

Handle 0x01A1, DMI type 15, 29 bytes
System Event Log
        Area Length: 16 bytes
        Header Start Offset: 0x0000
        Header Length: 16 bytes
        Data Start Offset: 0x0010
        Access Method: General-purpose non-volatile data functions
        Access Address: 0x0000
        Status: Invalid, Full
        Change Token: 0x00000036
        Header Format: Type 1
        Supported Log Type Descriptors: 3
        Descriptor 1: POST error
        Data Format 1: POST results bitmap
        Descriptor 2: Single-bit ECC memory error
        Data Format 2: Multiple-event
        Descriptor 3: Multi-bit ECC memory error
        Data Format 3: Multiple-event

Handle 0x0265, DMI type 23, 13 bytes
System Reset
        Status: Enabled
        Watchdog Timer: Present
        Boot Option: Do Not Reboot
        Boot Option On Limit: Do Not Reboot
        Reset Count: Unknown
        Reset Limit: Unknown
        Timer Interval: Unknown
        Timeout: Unknown

Handle 0x0268, DMI type 32, 20 bytes
System Boot Information
        Status: No errors detected

三，docker容器:

1,如果是虚拟机中安装的操作系统中运行docker,则上面两个方法在容器中是失效的

[root@centos /]# systemd-detect-virt 
vmware

这个错误，因为vmware是宿主机的虚拟平台

[root@centos /]# dmidecode -t system

返回也错误，因为返回的也是宿主机的信息

2，可以通过docker容器根分区专用的文件系统类型overlay来判断：

[root@centos /]# df -h / | grep overlay
overlay          50G   25G   23G  52% /

如果根分区文件系统是ovlerlay,表示是在docker容器中

3，通过dockerenv文件判断

[root@centos /]# ls /.dockerenv 
/.dockerenv

如果存在/.dockerenv文件，则是在docker容器中

4,根据/proc/1/cgroup是否包含docker字样判断

[root@centos /]# cat /proc/1/cgroup | grep docker
11:pids:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
10:freezer:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
9:cpu,cpuacct:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
8:perf_event:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
7:hugetlb:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
6:cpuset:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
5:blkio:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
4:net_cls,net_prio:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
3:memory:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
2:devices:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
1:name=systemd:/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286
/docker/ebe4fe937bb53c80227cb4772ea73888c381f639f97bee95ab06f0b976998286/init.scope

进程1的控制组是包含有docker的字样

四，systemd-detect-virt的用法 

1,列出支持检测的虚拟环境

[root@centos /]# systemd-detect-virt --list
none
kvm
qemu
bochs
xen
uml
vmware
oracle
microsoft
zvm
parallels
bhyve
qnx
vm-other
systemd-nspawn
lxc-libvirt
lxc
openvz
docker
rkt
container-other

2,非虚拟机或容器环境时，返回none

[root@centos /]# systemd-detect-virt
none

3,systemd-detect-virt查看版本

[root@centos /]# systemd-detect-virt --version      
systemd 239
+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default-hierarchy=legacy

4,只检测虚拟机

[root@centos /]# systemd-detect-virt -v 
vmware

5,只检测容器

[root@centos /]# systemd-detect-virt -c 
docker

说明：如果是虚拟机中的容器会检测不到