Cannot boot `php:*-apache` with `--tmpfs /run`

[twang2218]

I tried tmpfs with the php:5-apache and php:7-apache images, neither are working.

$ docker run --tmpfs /run php:5-apache
AH00526: Syntax error on line 3 of /etc/apache2/apache2.conf:
Invalid Mutex directory in argument file:/var/lock/apache2

$ docker run --tmpfs /run php:7-apache                                                                         
AH00526: Syntax error on line 3 of /etc/apache2/apache2.conf:
Invalid Mutex directory in argument file:/var/lock/apache2

I tried the httpd:latest image, it's ok with tmpfs:

$ docker run --tmpfs /run httpd:latest                                                                         
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.3. Set the 'ServerName' directive globally to suppress this message
AH00558: httpd: Could not reliably determine the server's fully qualified domain name, using 172.17.0.3. Set the 'ServerName' directive globally to suppress this message
[Mon Jul 04 04:51:01.359769 2016] [mpm_event:notice] [pid 1:tid 140197155190656] AH00489: Apache/2.4.20 (Unix) configured -- resuming normal operations
[Mon Jul 04 04:51:01.360029 2016] [core:notice] [pid 1:tid 140197155190656] AH00094: Command line: 'httpd -D FOREGROUND'

I tried this on both docker 1.12-rc2 on Mac and 1.11.2 on Ubuntu 16.04 server. Same result.

Here is my docker info:

$ docker info                                                                                                  
Containers: 17
 Running: 1
 Paused: 0
 Stopped: 16
Images: 72
Server Version: 1.12.0-rc2
Storage Driver: aufs
 Root Dir: /var/lib/docker/aufs
 Backing Filesystem: extfs
 Dirs: 263
 Dirperm1 Supported: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge null host overlay
Swarm: inactive
Runtimes: default
Default Runtime: default
Security Options: seccomp
Kernel Version: 4.4.14-moby
Operating System: Alpine Linux v3.4
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 1.954 GiB
Name: moby
ID: 7TAC:CSUC:6DR4:EZ3N:EMDQ:FAHS:NFV6:YRM5:ROAF:CH3F:ENBP:ANWT
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: 42
 Goroutines: 67
 System Time: 2016-07-04T04:51:47.379162935Z
 EventsListeners: 10
No Proxy: *.local, 169.254/16
Registry: https://index.docker.io/v1/
Experimental: true
Insecure Registries:
 127.0.0.0/8

[yosifkit]

The default config in the php:apache image comes with the following line, which is not in the httpd image:

Mutex file:/var/lock/apache2 default

In the image, /var/lock/ is a symlink to /run/lock/. By using the tmpfs on /run, the run directory is empty and the symlink from /var becomes invalid, making apache unable to resolve the path to the lock file.

[twang2218]

So, how to solve the problem?

Should I submit a PR to remove this line in the /etc/apache2/apache2.conf or add some code in the apache2-foreground to create the directory?

Currently, I cannot use the php:apache image with --read-only --tmpfs /run.

[twang2218]

After I remove the Mutex line,

RUN sed -i 's/Mutex.*/#&/' "$APACHE_CONFDIR/apache2.conf"

I still got error, bug another one.

root@d1:~/php# docker run --tmpfs /run myphp:5-apache
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using 172.17.0.2. Set the 'ServerName' directive globally to suppress this message
[Mon Nov 14 18:16:26.730476 2016] [core:error] [pid 1] (2)No such file or directory: AH00099: could not create /var/run/apache2/apache2.pid
[Mon Nov 14 18:16:26.730597 2016] [core:error] [pid 1] AH00100: apache2: could not log pid to file /var/run/apache2/apache2.pid

[twang2218]

After I remove both Mutex and PidFile, the image can boot with --tmpfs /run;

RUN sed -i 's/^Mutex.*/#&/g; s/^PidFile.*/#&/g' "$APACHE_CONFDIR/apache2.conf"

Should I create a PR for this?

[tianon]

That sounds reasonably sane IMO, given that the PID will usually be 1 and a Mutex shouldn't be required (since we're in a container already).

[twang2218]

@tianon I have submitted a PR #330 for this issue. Could you have a look?

[tianon]

Another easy runtime solution would be --tmpfs /run/lock (either instead or in addition to), which will ensure /run/lock is created as well.