Apache Server Fails To Start Due To Log Files Symlinked To Device Files.

[atikattar1104]

Context :-

Hi. I Am Trying To Install Nextcloud Standalone On My Stock Android Phone For Testing Purposes, Using Termux Linux Environment App, And uDocker, A Container Execution Software, Which Doesn't Require Root. I Have Tried Non-Docker, Tarball Extraction At Web Root Based Installation, Which Worked After Some Hiccups, But It Wasn't Maintainable Due To Constant Upgrades Of PHP, Breaking The Setup. So This Approach Feels Suitable For Stable Setup.

Issue :-

Here, I Am Facing An Issue With Apache Not Having Proper Permission To Access /var/log/apache2/error.log . This Is The Error I Got In STDOUT :-

AH00091: apache2: could not open error log file /var/log/apache2/error.log. AH00015: Unable to open logs 

Suspicion 1 :-

When I Tried To Investigate This, The error.log File Exists, But With crwxr--r-- Permission. Meaning, It Was Accessible As Character/Device File. Even Nano Said It's A Device File 😂.

Even If It's Content Is Funneled To /dev/null Or Something Similar (Since File Visible As Character/Device File), I Can Actually Read And Access The /dev/zero , /dev/null , /dev/random And /dev/urandom Paths. So That Shouldn't Be The Problem.

Suspicion 2 :-

When I Looked Up This Error On Internet, A Lot Of People Claimed, By Correctly Setting The SELinux Context Or Permission To The File, Solved The Problem. This Fix Is Not Possible For Me To Do, Since uDocker Does Not Have Support For Executing Commands Inside Container, Unlike Docker's exec Command.

As I Am Writing This, I Have An Idea. Maybe If I Mounted The Log Path Outside The Container To Host, That Might Solve The Problem. But IDK.

Let Me Test And Let You Know.

Workaround :-

Update :- Replicating The Same Files From /var/log/apache2/ From The Inside Of The Container, To Host Side, chmoding Their Permission To 777, And Bind Mounting Their Parent Folders To Each Other, Solved This Problem.

[joshtrichards]

This is what creates the error.log:

https://github.com/docker-library/php/blob/5c037abaf9dc0095e29807c048d9d1b97e6a9716/8.3/trixie/apache/Dockerfile#L87

[atikattar1104]

Update :- The Bind Mounting Of Log Folder Method Works. I Created The Same Files, Outside The Container, And Mounted The Parent Folder At The Same Log Folder, Completely Bypassing The Symlinked Paths.

[atikattar1104]

Rather Than Symlinking These Paths To Device Files, Maybe Just Let Them Be Normal Files. This Can Allow Access To These Logs For The Container Deployer, Which Then Can Be Externally Accessed Via Volume Binding.

[joshtrichards]

Rather Than Symlinking These Paths To Device Files, Maybe Just Let Them Be Normal Files.

This is an upstream (Official Docker PHP Base Image) feature. It's used to send Apache logs to the container logs. IIRC it's fairly common among the Official Images. I don't think it'll be changed unless someone makes a really compelling case.

Particularly since those that want something different can extend the image via their own Dockerfiles to customize as they see fit (or use any number of other approaches).

Glad you figured out an approach that works for you.