Ubuntu 이미지의 인스턴스를 생성하기 위해 다음 docker 명령을 실행했습니다.
docker run -it ubuntu bash
설치 명령을 실행하면 다음이 표시됩니다.
root@ca13e87462b5:/# mount
overlay on / type overlay (rw,relatime,lowerdir=/var/lib/docker/overlay2/l/O253SM3ZGX5EFP7OSBPPU5UW2C:/var/lib/docker/overlay2/l/IZEDWP7V4P4JWPLEL4EMN6GA5V:/var/lib/docker/overlay2/l/ZMFQPLBLMSGQYI7LDX5FSBHLEY:/var/lib/docker/overlay2/l/AVPGKJLG4AQJZLP3PKPGWQOMK6:/var/lib/docker/overlay2/l/6AFZ5ARHQ3PKYRWFQPUULZIMHB,upperdir=/var/lib/docker/overlay2/5a86c70a335f15d9c93bfb440b63b64aaef2b03b35ea42e3cef3609f96075514/diff,workdir=/var/lib/docker/overlay2/5a86c70a335f15d9c93bfb440b63b64aaef2b03b35ea42e3cef3609f96075514/work)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev type tmpfs (rw,nosuid,size=65536k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
sysfs on /sys type sysfs (ro,nosuid,nodev,noexec,relatime)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,relatime,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (ro,nosuid,nodev,noexec,relatime,xattr,name=systemd)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (ro,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/perf_event type cgroup (ro,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (ro,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/pids type cgroup (ro,nosuid,nodev,noexec,relatime,pids)
cgroup on /sys/fs/cgroup/rdma type cgroup (ro,nosuid,nodev,noexec,relatime,rdma)
cgroup on /sys/fs/cgroup/blkio type cgroup (ro,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/cpuset type cgroup (ro,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/freezer type cgroup (ro,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/devices type cgroup (ro,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/memory type cgroup (ro,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (ro,nosuid,nodev,noexec,relatime,hugetlb)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
/dev/sdb2 on /etc/resolv.conf type ext4 (rw,relatime,errors=remount-ro,data=ordered)
/dev/sdb2 on /etc/hostname type ext4 (rw,relatime,errors=remount-ro,data=ordered)
/dev/sdb2 on /etc/hosts type ext4 (rw,relatime,errors=remount-ro,data=ordered)
shm on /dev/shm type tmpfs (rw,nosuid,nodev,noexec,relatime,size=65536k)
devpts on /dev/console type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=666)
proc on /proc/bus type proc (ro,relatime)
proc on /proc/fs type proc (ro,relatime)
proc on /proc/irq type proc (ro,relatime)
proc on /proc/sys type proc (ro,relatime)
proc on /proc/sysrq-trigger type proc (ro,relatime)
tmpfs on /proc/asound type tmpfs (ro,relatime)
tmpfs on /proc/acpi type tmpfs (ro,relatime)
tmpfs on /proc/kcore type tmpfs (rw,nosuid,size=65536k,mode=755)
tmpfs on /proc/keys type tmpfs (rw,nosuid,size=65536k,mode=755)
tmpfs on /proc/timer_list type tmpfs (rw,nosuid,size=65536k,mode=755)
tmpfs on /proc/sched_debug type tmpfs (rw,nosuid,size=65536k,mode=755)
tmpfs on /proc/scsi type tmpfs (ro,relatime)
tmpfs on /sys/firmware type tmpfs (ro,relatime)
그래서 free disk 명령을 실행했는데...
root@ca13e87462b5:/# df -h
Filesystem Size Used Avail Use% Mounted on
overlay 219G 162G 46G 79% /
tmpfs 64M 0 64M 0% /dev
tmpfs 7.9G 0 7.9G 0% /sys/fs/cgroup
/dev/sdb2 219G 162G 46G 79% /etc/hosts
shm 64M 0 64M 0% /dev/shm
tmpfs 7.9G 0 7.9G 0% /proc/asound
tmpfs 7.9G 0 7.9G 0% /proc/acpi
tmpfs 7.9G 0 7.9G 0% /proc/scsi
tmpfs 7.9G 0 7.9G 0% /sys/firmware
/dev/sdb2 장치의 마운트 지점은 /etc/hosts 파일인 것 같습니다.
장치를 파일에 마운트할 수 있는지 몰랐습니다. 여기서 무슨 일이 일어나고 있는지 오해하고 있습니까?
/etc에서 ls를 실행하면 호스트가 파일이라는 것을 알 수 있습니다.
root@ca13e87462b5:/# ls -al /etc
total 268
drwxr-xr-x 1 root root 4096 Feb 24 17:40 .
drwxr-xr-x 1 root root 4096 Feb 24 17:40 ..
-rw------- 1 root root 0 Feb 4 21:03 .pwd.lock
-rw-r--r-- 1 root root 3028 Feb 4 21:03 adduser.conf
drwxr-xr-x 2 root root 4096 Feb 4 21:04 alternatives
drwxr-xr-x 1 root root 4096 Feb 4 21:03 apt
-rw-r--r-- 1 root root 2319 Apr 4 2018 bash.bashrc
-rw-r--r-- 1 root root 367 Jan 27 2016 bindresvport.blacklist
drwxr-xr-x 2 root root 4096 Feb 4 21:04 cron.daily
-rw-r--r-- 1 root root 2969 Feb 28 2018 debconf.conf
-rw-r--r-- 1 root root 11 Jun 25 2017 debian_version
drwxr-xr-x 2 root root 4096 Feb 4 21:04 default
-rw-r--r-- 1 root root 604 Aug 13 2017 deluser.conf
drwxr-xr-x 1 root root 4096 Feb 4 21:04 dpkg
-rw-r--r-- 1 root root 96 Feb 4 21:03 environment
-rw-r--r-- 1 root root 37 Feb 4 21:02 fstab
-rw-r--r-- 1 root root 2584 Feb 1 2018 gai.conf
-rw-r--r-- 1 root root 446 Feb 4 21:03 group
-rw-r----- 1 root shadow 374 Feb 4 21:03 gshadow
-rw-r--r-- 1 root root 92 Apr 9 2018 host.conf
-rw-r--r-- 1 root root 13 Feb 24 17:40 hostname
-rw-r--r-- 1 root root 174 Feb 24 17:40 hosts
drwxr-xr-x 2 root root 4096 Feb 4 21:04 init.d
-rw-r--r-- 1 root root 26 Aug 19 2018 issue
-rw-r--r-- 1 root root 19 Aug 19 2018 issue.net
drwxr-xr-x 3 root root 4096 Feb 4 21:03 kernel
-rw-r--r-- 1 root root 7274 Feb 4 21:04 ld.so.cache
-rw-r--r-- 1 root root 34 Jan 27 2016 ld.so.conf
drwxr-xr-x 2 root root 4096 Feb 4 21:04 ld.so.conf.d
-rw-r--r-- 1 root root 267 Apr 9 2018 legal
-rw-r--r-- 1 root root 191 Feb 7 2018 libaudit.conf
-rw-r--r-- 1 root root 10550 Jan 25 2018 login.defs
drwxr-xr-x 2 root root 4096 Feb 4 21:04 logrotate.d
-rw-r--r-- 1 root root 105 Aug 19 2018 lsb-release
-rw-r--r-- 1 root root 0 Feb 4 21:04 machine-id
-rw-r--r-- 1 root root 812 Mar 24 2018 mke2fs.conf
lrwxrwxrwx 1 root root 12 Feb 24 17:40 mtab -> /proc/mounts
-rw-r--r-- 1 root root 91 Apr 9 2018 networks
-rw-r--r-- 1 root root 497 Oct 5 2016 nsswitch.conf
drwxr-xr-x 2 root root 4096 Feb 4 21:02 opt
lrwxrwxrwx 1 root root 21 Aug 19 2018 os-release -> ../usr/lib/os-release
-rw-r--r-- 1 root root 552 Apr 4 2018 pam.conf
drwxr-xr-x 2 root root 4096 Feb 4 21:04 pam.d
-rw-r--r-- 1 root root 926 Feb 4 21:03 passwd
-rw-r--r-- 1 root root 581 Apr 9 2018 profile
drwxr-xr-x 2 root root 4096 Feb 4 21:04 profile.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc0.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc1.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc2.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc3.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc4.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc5.d
drwxr-xr-x 2 root root 4096 Oct 25 2017 rc6.d
drwxr-xr-x 2 root root 4096 Feb 4 21:03 rcS.d
-rw-r--r-- 1 root root 628 Feb 24 17:40 resolv.conf
-rwxr-xr-x 1 root root 268 Jul 21 2017 rmt
-rw-r--r-- 1 root root 4141 Jan 25 2018 securetty
drwxr-xr-x 4 root root 4096 Feb 4 21:03 security
drwxr-xr-x 2 root root 4096 Feb 4 21:04 selinux
-rw-r----- 1 root shadow 501 Feb 4 21:03 shadow
-rw-r--r-- 1 root root 73 Feb 4 21:03 shells
drwxr-xr-x 2 root root 4096 Feb 4 21:03 skel
-rw-r--r-- 1 root root 0 Feb 4 21:03 subgid
-rw-r--r-- 1 root root 0 Feb 4 21:03 subuid
-rw-r--r-- 1 root root 2683 Jan 17 2018 sysctl.conf
drwxr-xr-x 2 root root 4096 Feb 4 21:04 sysctl.d
drwxr-xr-x 3 root root 4096 Oct 25 2017 systemd
drwxr-xr-x 2 root root 4096 Feb 4 21:04 terminfo
drwxr-xr-x 2 root root 4096 Feb 4 21:04 update-motd.d
답변1
아니요. Docker는 파일을 파일에 묶어서 설치합니다.
에서 man 8 mount:
바인드 마운트
파일 계층 구조의 일부를 다른 곳에 다시 설치하십시오. 통화 내용은 다음과 같습니다.
mount --bind olddir newdir...
개별 파일을 (단일 파일에) 다시 마운트하는 것도 가능합니다.
Docker가 장치를 파일에 탑재하는 것처럼 보이는 이유는 mount -l명령 출력이 불완전하기 때문입니다. 즉, 바인드 탑재에 대한 소스 경로를 표시하지 않습니다.
다시 man 8 mount:
마운트 나열
목록 모드는 이전 버전과의 호환성을 위해서만 유지됩니다.
보다 강력하고 사용자 정의 가능한 출력을 위해서는 findmnt(8)를 사용하십시오.
실행 findmnt하면 번들에 마운트된 소스( 형식 device[source-path])가 표시됩니다.