CentOs 7: http won’t start at boot if it listens to a specific IP address

centoscentos7httpdrhel7systemd

I have this in my httpd.conf:

Listen 216.XX.YY.ZZZZ:80

Just to make sure, I made sure httpd is enabled at boot:

systemctl httpd enable

When the system boots, I have:

systemctl status httpd

● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Thu 2017-02-23 22:21:03 PST; 8min ago
  Process: 719 ExecStart=/usr/sbin/httpd $OPTIONS -DFOREGROUND (code=exited, status=1/FAILURE)
 Main PID: 719 (code=exited, status=1/FAILURE)

Feb 23 22:21:00 centosXXXXXX.aspadmin.net systemd[1]: Starting The Apache HTTP Server...
Feb 23 22:21:03 centosXXXXXX.aspadmin.net httpd[719]: (99)Cannot assign requested address: AH00072: make_sock: could not bind to address 216.XX.YY.XXX:80
Feb 23 22:21:03 centosXXXXXX.aspadmin.net httpd[719]: no listening sockets available, shutting down
Feb 23 22:21:03 centosXXXXXX.aspadmin.net httpd[719]: AH00015: Unable to open logs
Feb 23 22:21:03 centosXXXXXX.aspadmin.net systemd[1]: httpd.service: main process exited, code=exited, status=1/FAILURE
Feb 23 22:21:03 centosXXXXXX.aspadmin.net systemd[1]: Failed to start The Apache HTTP Server.
Feb 23 22:21:03 centosXXXXXX.aspadmin.net systemd[1]: Unit httpd.service entered failed state.
Feb 23 22:21:03 centosXXXXXX.aspadmin.net systemd[1]: httpd.service failed.

I can then start it by running:

systemctl start httpd

And everything works:

systemctl status httpd


● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
   Active: active (running) since Thu 2017-02-23 22:31:53 PST; 3s ago
 Main PID: 2804 (httpd)
   Status: "Processing requests..."
   CGroup: /system.slice/httpd.service
       ├─2804 /usr/sbin/httpd -DFOREGROUND
       ├─2805 /usr/sbin/httpd -DFOREGROUND
       ├─2806 /usr/sbin/httpd -DFOREGROUND
       ├─2808 /usr/sbin/httpd -DFOREGROUND
       ├─2824 /usr/sbin/httpd -DFOREGROUND
       └─2831 /usr/sbin/httpd -DFOREGROUND

Feb 23 22:31:53 centosXXXXXX.aspadmin.net systemd[1]: Starting The Apache HTTP Server...
Feb 23 22:31:53 centosXXXXXX.aspadmin.net httpd[2804]: AH00558: httpd:     Feb 23 22:31:53 centosXXXXXX.aspadmin.net systemd[1]: Started The Apache HTTP Server.
Hint: Some lines were ellipsized, use -l to show in full.

The IP is assigned to eth0 using a normal network script in /etc/sysconfig/network-scripts/ifcfg-eth0.

Checking /lib/systemd/system/httpd.service I have:

[Unit]
Description=The Apache HTTP Server
After=network.target remote-fs.target nss-lookup.target

The only similar problem on the net is here: https://unix.stackexchange.com/questions/207063/apache-httpd-failing-to-start-on-boot-centos-7 However, their advice:

systemctl enable NetworkManager-wait-online.service
Failed to execute operation: No such file or directory

Doesn't seem to work.

I am totally lost.

Best Answer

As it turns out, you need to use NetworkManager for this to work, since you want to wait for the IPs to actually be available. NetworkManager is not installed by default in CentOs 7.

So:

# yum install NetworkManager

Enable it:

systemctl enable NetworkManager-wait-online

Then:

# systemctl edit httpd.service

And add:

After=network.target NetworkManager-wait-online.service remote-fs.target nss-lookup.target

At this point, HTTPD will only start once the IP is assigned to the interface and bingo, it will actually start.

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