구차니의 잡동사니 모음

[root@localhost data]# ll

합계 48

-rw-r--r-- 1 root root 39852  8월  3  2017 default-testpage.pdf

-rw-r--r-- 1 root root   845  8월  3  2017 default.pdf

-rw-r--r-- 1 root root   234  8월  3  2017 testprint

[root@localhost data]# file *

default-testpage.pdf: PDF document, version 1.5

default.pdf:          PDF document, version 1.5

testprint:            ASCII text 

[root@localhost data]# cat testprint

#PDF-BANNER

Template default-testpage.pdf

Show printer-name printer-info printer-location printer-make-and-model printer-driver-name printer-driver-version paper-size imageable-area job-id options time-at-creation time-at-processing

$ escputil -P Stylus-C45 -m C45 -u -c 

#!/bin/bash

apt-get update

apt-get upgrade -y

apt-get autoclean 

$ sudo apt-get update; sudo apt-get upgrade

기존:1 http://ppa.launchpad.net/saiarcot895/myppa/ubuntu xenial InRelease

기존:2 http://ports.ubuntu.com/ubuntu-ports xenial InRelease

기존:3 http://ports.ubuntu.com/ubuntu-ports xenial-updates InRelease

기존:4 http://ports.ubuntu.com/ubuntu-ports xenial-backports InRelease

기존:5 http://ports.ubuntu.com/ubuntu-ports xenial-security InRelease

패키지 목록을 읽는 중입니다... 완료

E: /var/lib/dpkg/lock 잠금 파일을 얻을 수 없습니다 - open (11: Resource temporarily unavailable)

E: 관리 디렉터리를 (/var/lib/dpkg/) 잠글 수 없습니다. 다른 프로세스가 사용하고 있지 않습니까? 

~$ ps -ef | grep apt

root      2471     1  0 12:42 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily update

root      2475  2471  0 12:42 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily lock_is_held update

root      3743     1  0 12:45 ?        00:00:00 /bin/sh /usr/lib/apt/apt.systemd.daily install

$ sudo systemctl stop apt-daily.timer

$ sudo systemctl disable apt-daily.timer

$ sudo systemctl mask apt-daily.service

$ sudo systemctl daemon-reload 

/usr/lib/apt/apt.systemd.daily 

$ sudo vi /etc/apt/apt.conf.d/10periodic

APT::Periodic::Enable "0";

Systemd is all about concurrent start of services, so the cloud-init script is run at the same time the apt-daily.service is triggered. By the time cloud-init gets to execute the user-specified payload, apt-get update is already running. So the attempts 2. and 3. failed not because of some namespace magic, but because they altered the system too late for apt.systemd.daily to pick the changes up.

This also means that there is basically no way of preventing apt.systemd.daily from running -- one can only kill it after it's started.