nagios-4.2.4-2.el7 has been submitted as an update to Fedora EPEL 7. https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2017-0f3297a19b

nagios-4.2.4-2.el7 has been pushed to the Fedora EPEL 7 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2017-0f3297a19b

nagios-4.2.4-2.el7 has been pushed to the Fedora EPEL 7 stable repository. If problems still persist, please make note of it in this bug report.

I am seeing this problem on freshly installed CentOS 7 servers with nagios-4.2.4-2.el7.x86_64 


In /var/log/nagios/nagios.log

[1497967111] Unable to send check for host 'localhost' to worker (ret=-2)
[1497967118] Unable to run check for service 'PING' on host 'localhost'
[1497967134] Unable to send check for host 'foo' to worker (ret=-2)
[1497967171] Unable to send check for host 'localhost' to worker (ret=-2)
[1497967178] Unable to run check for service 'PING' on host 'localhost'
[1497967194] Unable to send check for host 'foo' to worker (ret=-2)


In /var/log/messages

Jun 20 15:17:13 new python: SELinux is preventing /usr/sbin/nagios from connectto access on the unix_stream_socket /var/spool/nagios/cmd/nagios.qh.#012#012*****  Plugin catchall_boolean (89.3 confidence) suggests   ******************#012#012If you want to allow daemons to enable cluster mode#012Then you must tell SELinux about this by enabling the 'daemons_enable_cluster_mode' boolean.#012#012Do#012setsebool -P daemons_enable_cluster_mode 1#012#012*****  Plugin catchall (11.6 confidence) suggests   **************************#012#012If you believe that nagios should be allowed connectto access on the nagios.qh unix_stream_socket by default.#012Then you should report this as a bug.#012You can generate a local policy module to allow this access.#012Do#012allow this access for now by executing:#012# ausearch -c 'nagios' --raw | audit2allow -M my-nagios#012# semodule -i my-nagios.pp#012


Older CentOS 7 servers running nagios that were set up when EPEL included nagios nagios-3.5.1-1.el7.x86_64 and have since been updated to nagios-4.2.4-2.el7.x86_64 work fine. Those have an selinux module called nagios-socket which is not present on freshly installed machines. On the older severs the file is located at

/etc/selinux/targeted/modules/active/modules/nagios-socket.pp

If does not belong to an rpm.


On a server which was originally installed with nagios-3.5.1-1.el7.x86_64 

[root@old ~]# sesearch -ACS -t nagios_t | grep unix_stream_soc | grep  nagios_t |  grep connectto
   allow nagios_t nagios_t : unix_stream_socket { ioctl read write create getattr setattr lock append bind connect listen accept getopt setopt shutdown connectto } ; 
[root@old ~]# 

On a server installed today

[root@new ~]# sesearch -ACS -t nagios_t | grep unix_stream_soc | grep  nagios_t |  grep connectto
[root@new ~]#


Copying nagios-socket.pp to and loading it on freshly installed server makes nagios checks work.

I can't work out where nagios-socket.pp comes from. I have not been able to find older versions of EPEL nagios rpm to examine to see if they provided it in a manner which caused it not to be removed on package upgrade.

Try:
yum -y install nagios-selinux
semodule -i /usr/share/selinux/packages/nagios/nagios_epel.pp