Jira (PUP-6675) Puppet::Util::Execution.execute 'hostname' returns nothing as daemon

[Michael Smith (JIRA)]

Title: Message Title

Michael Smith created an issue   Puppet / PUP-6675 Puppet::Util::Execution.execute 'hostname' returns nothing as daemon Issue Type: Bug Assignee: Unassigned Created: 2016/09/02 10:22 AM Priority: Normal Reporter: Michael Smith When Puppet::Util::Execution.execute 'hostname' is invoked by Puppet running as a daemon, no output is written. This seems to be exclusive to hostname, and may be restricted to certain Linux versions. I've tried it on RedHat 7 (64-bit). This can happen in a provider when using commands :hostname => 'hostname', and then invoking hostname. The root appears to be how /usr/bin/hostname handles file handles. This is getting into some core Ruby weirdness: ruby -e "Kernel.fork { \$stdout.reopen('/tmp/foo', 'w+'); Kernel.exec 'hostname' }" prints hostname to /tmp/foo when run from the command-line. When run as a systemd script: /usr/lib/systemd/system/print-hostname.service [Unit] Description=Print the hostname using Ruby Wants=basic.target After=basic.target network.target   [Service] ExecStart=/usr/bin/ruby -e "Kernel.fork { $stdout.reopen('/tmp/foo', 'w'); Kernel.exec 'hostname' }" KillMode=process   [Install] WantedBy=multi-user.target symlinked to /etc/systemd/system/multi-user.target.wants/print-hostname.service it creates an empty file. Changing the ruby script to foo = open('/tmp/foo', 'w'); pid = Kernel.fork { $stdout.reopen(foo); Kernel.exec 'hostname' }; Process.wait pid; foo.close to ensure the file is closed doesn't seem to change the behavior. Also, behavior is consistent with both system Ruby on Redhat 7 (2.0.0) and Ruby with a puppet-agent 1.6.2 build candidate. If I use a simple fork/exec without trying to redirect stdout, it prints correctly as a service and from the command-line. It's only once I redirect stdout that things get weird. The above is essentially what Puppet::Util::Execution.execute does, which is what the type is calling to. Interestingly, Facter::Core::Execution.execute (with Facter 3) works fine. With strace, I note that hostname calls write(1, ...) then immediately exits. Other examples will close fids 1 and 2 before exiting. Add Comment   This message was sent by Atlassian JIRA (v6.4.14#64029-sha1:ae256fe) -- You received this message because you are subscribed to the Google Groups "Puppet Bugs" group. To unsubscribe from this group and stop receiving emails from it, send an email to puppet-bugs+unsubscr...@googlegroups.com. To post to this group, send email to puppet-bugs@googlegroups.com. Visit this group at https://groups.google.com/group/puppet-bugs. For more options, visit https://groups.google.com/d/optout.