I am working on creating a backup script for some Docker contains. Some really strange thing happens when I copy files from a dir inside a Docker container to a host mounted dir - The files disappear.
EDIT: I managed to simplify the example and isolate the strange phenomenon:
#!/usr/bin/env bash
docker run -it --name gen_skeleton_cont \
mailman_server \
ls /etc && \
echo "Second ls:" && \
ls /etc \
# Cleanup the gen_skeleton_cont:
docker rm -f gen_skeleton_cont
The output of running this script is:
$ sudo bash check_incon.sh
Muttrc bash.bashrc cron.monthly environment hosts.allow issue.net logcheck mke2fs.conf os-release python rc6.d services sudoers ufw
Muttrc.d bash_completion.d cron.weekly fstab hosts.deny kbd login.defs modprobe.d pam.conf python2.7 rcS.d sgml sudoers.d update-motd.d
X11 bindresvport.blacklist crontab fstab.d init kernel logrotate.conf modules pam.d python3 resolv.conf shadow supervisor upstart-xsessions
adduser.conf blkid.conf dbus-1 gai.conf init.d ld.so.cache logrotate.d mtab passwd python3.4 resolvconf shadow- sysctl.conf vim
aliases blkid.tab debconf.conf group initramfs-tools ld.so.conf lsb-release network passwd- rc.local rmt shells sysctl.d vtrgb
aliases.db ca-certificates debian_version group- inputrc ld.so.conf.d magic networks perl rc0.d rpc skel syslog-ng wgetrc
alternatives ca-certificates.conf default gshadow insserv ldap magic.mime newt postfix rc1.d rsyslog.conf ssl systemd xml
apache2 console-setup deluser.conf gshadow- insserv.conf legal mailcap nologin ppp rc2.d rsyslog.d subgid terminfo
apparmor cron.d depmod.d host.conf insserv.conf.d libaudit.conf mailcap.order nsswitch.conf profile rc3.d securetty subgid- timezone
apparmor.d cron.daily dhcp hostname iproute2 locale.alias mailman ntp.conf profile.d rc4.d security subuid ucf.conf
apt cron.hourly dpkg hosts issue localtime mime.types opt protocols rc5.d selinux subuid- udev
Second ls:
acpi ca-certificates.conf dhcp host.conf kbd lsb-release opt python3.4 screenrc sudoers w3m
adduser.conf calendar digitalocean hostname kernel ltrace.conf os-release rc0.d securetty sudoers.d wgetrc
alternatives chatscripts dpkg hosts kernel-img.conf magic pam.conf rc1.d security sysctl.conf wireshark
apm cloud environment hosts.allow landscape magic.mime pam.d rc2.d selinux sysctl.d wpa_supplicant
apparmor console-setup fish hosts.deny ldap mailcap passwd rc3.d services systemd X11
apparmor.d cron.d fonts ifplugd ld.so.cache mailcap.order passwd- rc4.d sgml terminfo xml
apport cron.daily fstab init ld.so.conf manpath.config perl rc5.d shadow timezone zsh_command_not_found
apt cron.hourly fstab.d init.d ld.so.conf.d mime.types pm rc6.d shadow- ucf.conf
at.deny cron.monthly fuse.conf initramfs-tools legal mke2fs.conf polkit-1 rc.digitalocean shells udev
bash.bashrc crontab gai.conf inputrc libaudit.conf modprobe.d popularity-contest.conf rc.local skel ufw
bash_completion cron.weekly groff insserv libnl-3 modules ppp rcS.d smi.conf updatedb.conf
bash_completion.d dbus-1 group insserv.conf locale.alias mtab profile resolvconf ssh update-manager
bindresvport.blacklist debconf.conf group- insserv.conf.d localtime nanorc profile.d resolv.conf ssl update-motd.d
blkid.conf debian_version grub.d iproute2 logcheck network protocols rmt subgid update-notifier
blkid.tab default gshadow iscsi login.defs networks python rpc subgid- upstart-xsessions
byobu deluser.conf gshadow- issue logrotate.conf newt python2.7 rsyslog.conf subuid vim
ca-certificates depmod.d hdparm.conf issue.net logrotate.d nsswitch.conf python3 rsyslog.d subuid- vtrgb
gen_skeleton_cont
As can be seen, the two invocations of ls give different results. Maybe the container hasn't finished loading? I must be missing something.
If it helps, the full repository is here (Including Docker files): https://github.com/realcr/mailman_docker
I think I found the problem. It is not related to Docker at all. It's a bash thing.
When invoking:
docker run -it --name gen_skeleton_cont \
mailman_server \
ls /etc && \
echo "Second ls:" && \
ls /etc \
The first ls happens inside the Docker container, however the second one happens inside the host machine. I should find some other way to run multiple commands inside a Docker container, maybe using another .sh file.