salt: host.present may break /etc/hosts file format

Dear all,

using host.present to add an host with alias names to /etc/hosts may break the file format as explained below.

I am not sure whether this is merely a case of unexpected behavior or wrong usage by me or might indeed qualify as a bug.

The format of a line in /etc/hosts on an unixoid system is fixed as IP_address canonical_hostname [aliases...] so to be more concrete usually 10.10.10.111 test.example.com test please confirm with man (5) hosts. The FQDN has to be in front of the short-hand alias.

Naively using host.present to add the whole line 10.10.10.111 test.example.com test in one call generates instead:

test_input:
  host.present:
    - ip: 10.10.10.111
    - names:
      - fqdn.domain.com
      - alias

Generated line in the minions /etc/hosts: 10.10.10.111 alias fqdn.domain.com

test_input:
  host.present:
    - ip: 10.10.10.111
    - names:
      - alias
      - fqdn.domain.com

Generated line in the minions /etc/hosts: 10.10.10.111 alias fqdn.domain.com

Both break /etc/hosts format, the alias is in front of the FQDN.

Calling host.present twice can be used to generate the correct order of entries as shown below

input_fqdn:
  host.present:
    - ip: 10.10.10.111
    - names:
      - fqdn.domain.com

input_alias:
  host.present:
    - ip: 10.10.10.111
    - names:
      - alias

Generated line in the minions /etc/hosts: 10.10.10.111 fqdn.domain.com alias

but is awkward.

In any case I would suggest to mention this behavior in the salt.states.host documentation. If generating an FQDN and several aliases for one IP with one call of host.present is not the intended use case of the option to pass several names as a list (so in case I am using the features of host.present in a wrong way) it would also be nice to document the intended use.

Best Regards

Christof

Salt Version information:

Master

 Salt Version:
           Salt: 2015.8.3

Dependency Versions:
         Jinja2: 2.7.3
       M2Crypto: Not Installed
           Mako: 1.0.0
         PyYAML: 3.11
          PyZMQ: 14.4.0
         Python: 2.7.9 (default, Mar  1 2015, 12:57:24)
           RAET: Not Installed
        Tornado: 4.2.1
            ZMQ: 4.0.5
           cffi: 0.8.6
       cherrypy: Not Installed
       dateutil: 2.2
          gitdb: 0.5.4
      gitpython: 0.3.2 RC1
          ioflo: Not Installed
        libnacl: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.4.2
   mysql-python: 1.2.3
      pycparser: 2.10
       pycrypto: 2.6.1
         pygit2: Not Installed
   python-gnupg: Not Installed
          smmap: 0.8.2
        timelib: Not Installed

System Versions:
           dist: debian 8.2 
        machine: x86_64
        release: 3.16.0-4-amd64
         system: debian 8.2

Minion

Salt Version:
           Salt: 2015.8.3

Dependency Versions:
         Jinja2: 2.7.2
       M2Crypto: Not Installed
           Mako: 0.9.1
         PyYAML: 3.10
          PyZMQ: 14.0.1
         Python: 2.7.6 (default, Jun 22 2015, 17:58:13)
           RAET: Not Installed
        Tornado: 4.2.1
            ZMQ: 4.0.4
           cffi: Not Installed
       cherrypy: Not Installed
       dateutil: 1.5
          gitdb: Not Installed
      gitpython: Not Installed
          ioflo: Not Installed
        libnacl: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.3.0
   mysql-python: 1.2.3
      pycparser: Not Installed
       pycrypto: 2.6.1
         pygit2: Not Installed
   python-gnupg: Not Installed
          smmap: Not Installed
        timelib: Not Installed

System Versions:
           dist: Ubuntu 14.04 trusty
        machine: x86_64
        release: 3.13.0-57-generic
         system: Ubuntu 14.04 trusty

About this issue

Original URL
State: closed
Created 9 years ago
Comments: 22 (16 by maintainers)

Most upvoted comments

For the record, this is still not working (tested with 2016.3.1).

This is very dependent on fqdn and alias name.

common_hostsfile:
  host.present:
    - ip: 10.10.10.123
    - names:
      - foo 
      - foo.local.domain

Will give:

10.10.10.123 foo.local.domain foo

But

test_input:
  host.present:
    - ip: 10.10.10.111
    - names:
      - fqdn.domain.com
      - alias

Will give:

10.10.10.111 alias fqdn.domain.com

It will be great if this can be fixed in future release.

alssi on Jul 13, 2016

The extra option can be optional. I really like that or you can try to check for dots in hostnames, but is a bit hacky, you can also search in hostnames for the current hostname + domain in that list, still hacky. Like I always say, there is no tool to fix human issues 😃 You can create some complex logic to try to determine which is the best entry to use as FQDN, which will work in simple cases, but nit in complex ones. A simple option could be, the first entry is hostnames is used as FQDN, all other as alias, no extra option, simple to implement and if is well documented, problem fixed 😃

abednarik on Aug 31, 2017