Description of problem:
SELinux is preventing unbound-anchor from 'map' accesses on the file /etc/ld.so.cache.

*****  Plugin restorecon (94.8 confidence) suggests   ************************

If you want to fix the label. 
/etc/ld.so.cache default label should be ld_so_cache_t.
Then you can run restorecon. The access attempt may have been stopped due to insufficient permissions to access a parent directory in which case try to change the following command accordingly.
Do
# /sbin/restorecon -v /etc/ld.so.cache

*****  Plugin catchall_labels (5.21 confidence) suggests   *******************

If you want to allow unbound-anchor to have map access on the ld.so.cache file
Then you need to change the label on /etc/ld.so.cache
Do
# semanage fcontext -a -t FILE_TYPE '/etc/ld.so.cache'
where FILE_TYPE is one of the following: file_context_t, fonts_cache_t, fonts_t, ld_so_cache_t, ld_so_t, lib_t, locale_t, named_checkconf_exec_t, named_exec_t, prelink_exec_t, sssd_public_t, textrel_shlib_t, usr_t.
Then execute:
restorecon -v '/etc/ld.so.cache'


*****  Plugin catchall (1.44 confidence) suggests   **************************

If you believe that unbound-anchor should be allowed map access on the ld.so.cache file by default.
Then you should report this as a bug.
You can generate a local policy module to allow this access.
Do
allow this access for now by executing:
# ausearch -c 'unbound-anchor' --raw | audit2allow -M my-unboundanchor
# semodule -X 300 -i my-unboundanchor.pp

Additional Information:
Source Context                system_u:system_r:named_t:s0
Target Context                system_u:object_r:etc_t:s0
Target Objects                /etc/ld.so.cache [ file ]
Source                        unbound-anchor
Source Path                   unbound-anchor
Port                          <Unknown>
Host                          (removed)
Source RPM Packages           
Target RPM Packages           glibc-2.26-27.fc27.x86_64
Policy RPM                    selinux-policy-3.13.1-283.26.fc27.noarch
Selinux Enabled               True
Policy Type                   targeted
Enforcing Mode                Enforcing
Host Name                     (removed)
Platform                      Linux (removed) 4.15.9-300.fc27.x86_64 #1 SMP Mon
                              Mar 12 17:07:55 UTC 2018 x86_64 x86_64
Alert Count                   1
First Seen                    2018-03-20 12:17:59 IST
Last Seen                     2018-03-20 12:17:59 IST
Local ID                      00656707-fbea-4be0-a9b9-840966612bfc

Raw Audit Messages
type=AVC msg=audit(1521528479.590:103): avc:  denied  { map } for  pid=745 comm="unbound-anchor" path="/etc/ld.so.cache" dev="dm-0" ino=264561 scontext=system_u:system_r:named_t:s0 tcontext=system_u:object_r:etc_t:s0 tclass=file permissive=0


Hash: unbound-anchor,named_t,etc_t,file,map

Version-Release number of selected component:
selinux-policy-3.13.1-283.26.fc27.noarch

Additional info:
component:      selinux-policy
reporter:       libreport-2.9.3
hashmarkername: setroubleshoot
kernel:         4.15.9-300.fc27.x86_64
type:           libreport