Aspnetcore.docs: Linux with Apache topic issues

[davidich]

According to this guide, httpd-2.4.6-40.el7.centos.4.x86_64.rpm is good enough to proceed, but "service httpd configtest" command fails with an error: "Unrecognized header format %". I was able to solve it by installing the latest version of httpd (Apache/2.4.33).

Env details:

• Operating System: CentOS Linux 7 (Core)
• CPE OS Name: cpe:/o:centos:centos:7
• Kernel: Linux 3.10.0-693.21.1.el7.x86_64
• Architecture: x86-64

Moved from #6828 ...

> ExecStart=/usr/local/bin/dotnet /var/aspnetcore/hellomvc/hellomvc.dll
there is no file dotnet in /usr/local/bin
I guess it should be one of the following:

• /usr/bin/dotnet
• /usr/share/dotnet/dotnet

Env details:

• .NET Core 2.1 Runtime (v2.1.0)
• Operating System: CentOS Linux 7 (Core)
• CPE OS Name: cpe:/o:centos:centos:7
• Kernel: Linux 3.10.0-693.21.1.el7.x86_64
• Architecture: x86-64

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: cfd9a1f0-c1b6-4443-0700-4c5beafeed03
• Version Independent ID: c22ca7a0-d1d4-200d-fc36-a9798d350c6e
• Content: Host ASP.NET Core on Linux with Apache
• Content Source: aspnetcore/host-and-deploy/linux-apache.md
• Product: asp.net-core
• GitHub Login: @spboyer
• Microsoft Alias: spboyer

[guardrex]

Thanks @davidich for the report.

@shirhatti How do you want to proceed?

[user135711]

To be specific the error occurs below 2.4.10, so until centos repos advance beyond, I solved by installing from the non centos repo (instructions from here). Also, I kept getting "Config variable ${APACHE_LOG_DIR} is not defined" until I hard coded the variable reference in hellomvc.conf for ${APACHE_LOG_DIR} to "/etc/httpd/logs/" so perhaps that could be addressed in this update if anyone else reports it. There are many solutions for Ubuntu but I couldn't find a solution on centos.
I also had to set the ServerName in /etc/httpd/conf/httpd.conf which was not in the tutorial to resolve a warning similar to the following:
"Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message"

---

I also had to change the 00-mpm.conf module from
LoadModule mpm_worker_module modules/mod_mpm_worker.so
to
LoadModule mpm_prefork_module modules/mod_mpm_prefork.so
I forget what error required this change for the server to start.

There also remained a non critical permission issue writing to the custom log file /etc/httpd/${APACHE_LOG_DIR}hellomvc-error.log. that I don't care about because it didn't prevent the server from running.

---

One final edit I had to make was due to CentOS restricting access to everything: After setting up TLS, I got a 503 Service Unavailable error from the site and the solution is hidden in the top right corner of SELinux notifications:

SELinux is preventing /usr/sbin/httpd from name_connect access on the tcp_socket port 5000.

Plugin catchall_boolean (89.3 confidence) suggests *****

If you want to allow httpd to can network connect
Then you must tell SELinux about this by enabling the 'httpd_can_network_connect' boolean.

Do
setsebool -P httpd_can_network_connect 1
I had to run this bold line for the site to work.

[Rick-Anderson]

@shirhatti please comment

[shirhatti]

To be specific the error occurs below 2.4.10, so until centos repos advance beyond, I solved by installing from the non centos repo (instructions from here). Also, I kept getting "Config variable ${APACHE_LOG_DIR} is not defined" until I hard coded the variable reference in hellomvc.conf for ${APACHE_LOG_DIR} to "/etc/httpd/logs/" so perhaps that could be addressed in this update if anyone else reports it. There are many solutions for Ubuntu but I couldn't find a solution on centos.

While I understand, that solved your issue. I'm not keen on recommending a package maintained by some third-party (CodeIT in this case) in our official docs. I wouldn't mind if it were the vendor itself (i.e., Apache foundation).

The options I see are either:

1. See if there is a vendor supported way of installing Apache >= 2.4.10
2. Let the reader figure it out for themselves

---

"Could not reliably determine the server's fully qualified domain name, using 127.0.1.1. Set the 'ServerName' directive globally to suppress this message"

I'm okay adding a note about it, but I don't really mind since it's a non-critical warning

---

One final edit I had to make was due to CentOS restricting access to everything: After setting up TLS, I got a 503 Service Unavailable error from the site and the solution is hidden in the top right corner of SELinux notifications:

Sorry folks. I know nothing about SELinux. Perhaps we just add a note saying you may need additional AppArmor or SELinux configuration for this to run?
@blowdart How do you want to address Linux security guidance for running our stuff?

[blowdart]

Carefully checked and validated community contributions by someone that knows Linux security? SELinux is going into unsupported territory probably.

[user135711]

@shirhatti I agree with blowdart's point. This documentation is about ASP.NET Core, not linux. Best to stick to the topic. However, I don't see why not fix the bugs. The server wouldn't start until I hard coded the log directory for 2 references to ${APACHE_LOG_DIR} in hellomvc.conf and added the domain for a ServerName in /etc/httpd/conf/httpd.conf. There was a third separate error that didn't prevent the server from starting regarding write permissions to /etc/httpd/${APACHE_LOG_DIR}/hellomvc-error.log which I was able ignore.

The options I see are either:

See if there is a vendor supported way of installing Apache >= 2.4.10
Let the reader figure it out for themselves
Or edit the line to use different syntax, or just wait. The version installed from the official repo was 2.4.06.

[twoCansOfTomatoes]

Running the configtest gives me below warnings

_sudo service httpd configtest_

[core:warn] [pid 5654:tid 140675401267392] AH00111: Config variable ${APACHE_LOG_DIR} is not defined
[core:warn] [pid 5654:tid 140675401267392] AH00111: Config variable ${APACHE_LOG_DIR} is not defined
Syntax OK

This happened even after upgrading my httpd to 2.4.33 as suggested by @user135711
httpd fails to restart.

However, https restarts successfully after I hardcode it. Please suggest where to set these variables.

[user135711]

@ParidaPunyasloka Yes, that's what this trouble ticket is about. The "Unrecognized header format %" syntax which requires the upgrade. The ${APACHE_LOG_DIR} is a different issue I added to the ticket and fixed by hard coding.

[guardrex]

This doesn't seem very actionable from a docs perspective. See: #9853 ... I'll close since there isn't much we can do here.