diff options
| -rw-r--r-- | cloudinit/CloudConfig/cc_update_etc_hosts.py | 36 | ||||
| -rw-r--r-- | doc/examples/cloud-config.txt | 106 |
2 files changed, 89 insertions, 53 deletions
diff --git a/cloudinit/CloudConfig/cc_update_etc_hosts.py b/cloudinit/CloudConfig/cc_update_etc_hosts.py index 6012b8a3..1dc9c1e9 100644 --- a/cloudinit/CloudConfig/cc_update_etc_hosts.py +++ b/cloudinit/CloudConfig/cc_update_etc_hosts.py @@ -24,25 +24,29 @@ frequency = per_always def handle(name,cfg,cloud,log,args): ( hostname, fqdn ) = util.get_hostname_fqdn(cfg, cloud) - use_template = util.get_cfg_option_bool(cfg,"manage_etc_hosts", False) - if not use_template: - # manage_etc_hosts not true, update the 127.0.1.1 entry via update_etc_hosts - log.debug("manage_etc_hosts is not set, checking sanity of /etc/hosts") + manage_hosts = util.get_cfg_option_bool(cfg,"manage_etc_hosts", False) + if manage_hosts in ("True", "true", True, "template"): + # render from template file + try: + if not hostname: + log.info("manage_etc_hosts was set, but no hostname found") + return + + util.render_to_file('hosts', '/etc/hosts', \ + { 'hostname' : hostname, 'fqdn' : fqdn }) + except Exception as e: + log.warn("failed to update /etc/hosts") + raise + elif manage_hosts == "localhost": + log.debug("managing 127.0.1.1 in /etc/hosts") update_etc_hosts(hostname, fqdn, log) return + else: + if manage_hosts not in ("False", False): + log.warn("Unknown value for manage_etc_hosts. Assuming False") + else: + log.debug("not managing /etc/hosts") - # manage_etc_hosts is set, render from template file - try: - if not hostname: - log.info("manage_etc_hosts was set, but no hostname found") - return - - util.render_to_file('hosts', '/etc/hosts', \ - { 'hostname' : hostname, 'fqdn' : fqdn }) - - except Exception as e: - log.warn("failed to update /etc/hosts") - raise def update_etc_hosts(hostname, fqdn, log): with open('/etc/hosts', 'r') as etchosts: diff --git a/doc/examples/cloud-config.txt b/doc/examples/cloud-config.txt index e73b8743..3c9e4b2e 100644 --- a/doc/examples/cloud-config.txt +++ b/doc/examples/cloud-config.txt @@ -341,48 +341,80 @@ rsyslog: resize_rootfs: True ## hostname and /etc/hosts management -# cloud-init will do its best to set up a sane hostname and corresponding -# entries in /etc/hosts. -# -# if you do nothing, you should get the system generally correctly -# configured. -# * /etc/hostname (and thus `hostname` output) set with hostname (not fqdn) -# * an entry in /etc/hosts for both hostname and fqdn -# that are obtained from the metadata service -# * On each boot, the above will again be set -# * cloud-init generally "owns" the 127.0.1.1 entry. The -# rest of the file will not be modified +# cloud-init can handle updating some entries in /etc/hosts, +# and can set your hostname for you. +# +# if you do nothing you'll end up with: +# * /etc/hostname (and `hostname`) managed via: 'preserve_hostame: false' +# if you do not change /etc/hostname, it will be updated with the cloud +# provided hostname on each boot. If you make a change, then manual +# maintenance takes over, and cloud-init will not modify it. +# +# * /etc/hosts managed via: 'manage_etc_hosts: false' +# cloud-init will not manage /etc/hosts at all. It is in full manual +# maintenance mode. # # You can change the above behavior with the following config variables: # Remember that these can be set in cloud-config via user-data, # /etc/cloud/cloud.cfg or any file in /etc/cloud/cloud.cfg.d/ # -# hostname: -# this option will be used wherever the 'hostname' is needed -# simply substitute it in the description above. -# ** If you wish to set your hostname, set it here ** -# default: 'hostname' as returned by the metadata service -# on EC2, the hostname portion of 'local-hostname' is used -# which is something like 'ip-10-244-170-199' -# -# fqdn: -# this option will be used wherever 'fqdn' is needed. -# simply substitue it in the description above. -# default: fqdn as returned by the metadata service. on EC2 'hostname' -# is used, so this is like: ip-10-244-170-199.ec2.internal -# -# manage_etc_hosts: -# default: false -# Setting this config variable to 'true' will mean that on every -# boot, /etc/hosts will be re-written from /etc/cloud/templates/hosts.tmpl -# The strings '$hostname' and '$fqdn' are replaced in the template -# with the appropriate values. -# -# preserve_hostname: -# default: False -# If this option is set to True, then /etc/hostname will never updated -# The default behavior is to update it if it has not been modified by -# the user. +# == Hostname management (via /etc/hostname) == +# * preserve_hostname: +# default: False +# If this option is set to True, then /etc/hostname will never updated +# The default behavior is to update it if it has not been modified by +# the user. +# +# * hostname: +# this option will be used wherever the 'hostname' is needed +# simply substitute it in the description above. +# ** If you wish to set your hostname, set it here ** +# default: 'hostname' as returned by the metadata service +# on EC2, the hostname portion of 'local-hostname' is used +# which is something like 'ip-10-244-170-199' +# +# * fqdn: +# this option will be used wherever 'fqdn' is needed. +# simply substitue it in the description above. +# default: fqdn as returned by the metadata service. on EC2 'hostname' +# is used, so this is like: ip-10-244-170-199.ec2.internal +# +# == /etc/hosts management == +# +# The cloud-config variable that covers management of /etc/hosts is +# 'manage_etc_hosts' +# +# By default, its value is 'false' (boolean False) +# +# * manage_etc_hosts: +# default: false +# +# false: +# cloud-init will not modify /etc/hosts at all. +# * Whatever is present at instance boot time will be present after boot. +# * User changes will not be overwritten +# +# true or 'template': +# on every boot, /etc/hosts will be re-written from +# /etc/cloud/templates/hosts.tmpl. +# The strings '$hostname' and '$fqdn' are replaced in the template +# with the appropriate values. +# To make modifications persistant across a reboot, you must make +# modificatoins to /etc/cloud/templates/hosts.tmpl +# +# localhost: +# This option ensures that an entry is present for fqdn as described in +# section 5.1.2 of the debian manual +# http://www.debian.org/doc/manuals/debian-reference/ch05.en.html +# +# cloud-init will generally own the 127.0.1.1 entry, and will update +# it to the hostname and fqdn on every boot. All other entries will +# be left as is. 'ping `hostname`' will ping 127.0.1.1 +# +# If you want a fqdn entry with aliases other than 'hostname' to resolve +# to a localhost interface, you'll need to use something other than +# 127.0.1.1. For example: +# 127.0.1.2 myhost.fqdn.example.com myhost whatup.example.com # final_message # default: cloud-init boot finished at $TIMESTAMP. Up $UPTIME seconds |