Instalation error: httpd: apr_sockaddr_info_get() failed

[J0aquin]

Hello,

I am trying to install Nagios Core 4.0.8 on CentOS 6.6 (64 bits). I have tried it on both full verision of the CentOS and the minimal version too. I am following the instructions on:

http://library.nagios.com/library/produ ... rom-source

and in both cases I got the same error. When I reach the instrution:

For RHEL/CentOS users:
/etc/init.d/httpd start

I get the error:

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Starting httpd: httpd: apr_sockaddr_info_get() failed for COMPUTERNAME
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
                                                                 [ OK  ]

The httpd is running but it can not be seen from a web browser outside the server.

I have seen something similar for NagiosXI in other forums but not in this one with a solution specific for this conbination.

Could you help me please?

[rhassing]

I think it might be an firewall problem.
Please check if http is allowed in your iptable config.

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iptables -L

This should give a list of iptables items, and also:

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ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:http

If this line is not in there you could add it by typing setup (should work in CentOS).
Or you could edit the file "/etc/sysconfig/iptables" and copy a line (probably ssh/port 22 is in there) and replace the 22 with 80 for http.

Restart the iptables service after you changed it "/etc/init.d/iptables restart"

[J0aquin]

Thank you. Effectively that line is not in iptables. I execute:

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iptables -A INPUT -p TCP --dport 80 -j ACCEPT

and when I execute

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iptables -L

the following line is in there:

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ACCEPT tcp  --  anywhere   anywhere  tcp  dpt:http

I restart the httpd:

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/etc/init.d/httpd restart

but it gives me the same message:

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Starting httpd: httpd: apr_sockaddr_info_get() failed for COMPUTERNAME
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName

And the web server can not be accessed from a web browser in another computer.

Furthermore, if I restart the nagios server that I am configuring the httpd is running but if I excute

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iptables -L

again, the addition made before is not there and the list of rules is the same as the beginig.

Please, any idea on what could be happening?

[rhassing]

The error you get from the httpd is not really important. It's just a message your hostname could not be resolved.

For the iptables problem you should either use the "setup" command, or you should adjust the file "/etc/sysconfig/iptables" or use "iptables-save" after you added the line like described.

[rhassing]

I can reproduce the problem on a virtual machine:

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[root@rhel6 ]# /etc/init.d/httpd restart
Stopping httpd:                                            [FAILED]
Starting httpd: httpd: apr_sockaddr_info_get() failed for [b]rhel6[/b]
httpd: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
                                                           [  OK  ]
[root@rhel6 ]#

add the computername (in my case rhel6) to the line with 127.0.0.1 in the /etc/hosts file

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[root@rhel6 ]# cat /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4 rhel6
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
[root@rhel6 ]# 

Change "/etc/httpd/conf/httpd.conf" and adjust the line which starts with "ServerName". uncomment it and change it to your hostname.

I have changed it to:

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ServerName rhel6:80

The hostname should be in the "/etc/hosts" file as well.

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[root@rhel6 ]# /etc/init.d/httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]
[root@rhel6 ]#

My iptables looks like this:

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[root@rhel6 ~]# iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere            state RELATED,ESTABLISHED 
ACCEPT     icmp --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     tcp  --  anywhere             anywhere            state NEW tcp dpt:ssh 
REJECT     all  --  anywhere             anywhere            reject-with icmp-host-prohibited 

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
REJECT     all  --  anywhere             anywhere            reject-with icmp-host-prohibited 

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
[root@rhel6 ~]# 

I changed the file "/etc/sysconfig/iptables":

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vi /etc/sysconfig/iptables

Before:

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# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

After:

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# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

[J0aquin]

Thank you. I added the line:

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-A INPUT -p tcp -M state –state NEW -m tcp –dport 80 -j ACCEPT

to the /etc/sysconfig/iptables file and could get to the nagios page OK from another computer.

I also introduced the serverName in the conifg files indicated:

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/etc/hosts
/etc/httpd/conf/httpd.conf

and you con run

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/etc/init.d/httpd restart

without any error message.

These two problems are solved. Now when I enter the Nagios Core web page, at the home page I see:

"Unable to get process status"

I have gone through the whole process of installing the Nagios Core again just in case the problems where related but it is still the same. I do not think the problem in this thread and this other problem are related so I will open a different thread.

thank you

[tmcdonald]

Sounds good. I will close this one up and we'll see you in the other thread.