def start_datanode(namenode):
hookenv.status_set('maintenance', 'starting datanode')
# NB: service should be started by install, but we want to verify it is
# running before we set the .started state and open ports. We always
# restart here, which may seem heavy-handed. However, restart works
# whether the service is currently started or stopped. It also ensures the
# service is using the most current config.
started = host.service_restart('hadoop-hdfs-datanode')
if started:
# Create a /user/ubuntu dir in HDFS (this is safe to run multiple times).
bigtop = Bigtop()
if not bigtop.check_hdfs_setup():
try:
utils.wait_for_hdfs(30)
bigtop.setup_hdfs()
except utils.TimeoutError:
# HDFS is not yet available or is still in safe mode, so we can't
# do the initial setup (create dirs); skip setting the .started
# state below so that we try again on the next hook.
hookenv.status_set('waiting', 'waiting on hdfs')
return
# HDFS is ready. Open ports and set .started, status, and app version
for port in get_layer_opts().exposed_ports('datanode'):
hookenv.open_port(port)
set_state('apache-bigtop-datanode.started')
hookenv.status_set('maintenance', 'datanode started')
hookenv.application_version_set(get_hadoop_version())
else:
hookenv.log('DataNode failed to start')
hookenv.status_set('blocked', 'datanode failed to start')
remove_state('apache-bigtop-datanode.started')
for port in get_layer_opts().exposed_ports('datanode'):
hookenv.close_port(port)
