Most Block Storage errors are caused by incorrect volume
configurations that result in volume creation failures. To resolve these
failures, review these logs:

• cinder-api log
  (/var/log/cinder/api.log)
• cinder-volume log
  (/var/log/cinder/volume.log)

The cinder-api log is useful for determining if you have
endpoint or connectivity issues. If you send a request to create a
volume and it fails, review the cinder-api log to determine
whether the request made it to the Block Storage service. If the request
is logged and you see no errors or tracebacks, check the
cinder-volume log for errors or tracebacks.

These entries in the cinder.conf file can be used to
assist in troubleshooting your Block Storage configuration.

# Print debugging output (set logging level to DEBUG instead
# of default WARNING level). (boolean value)
# debug=false

# Log output to standard error (boolean value)
# use_stderr=true

# Default file mode used when creating log files (string
# value)
# logfile_mode=0644

# format string to use for log messages with context (string
# value)
# logging_context_format_string=%(asctime)s.%(msecs)03d %(levelname)s
# %(name)s [%(request_id)s %(user)s %(tenant)s] %(instance)s%(message)s

# format string to use for log mes #logging_default_format_string=%(asctime)s.
# %(msecs)03d %(process)d %(levelname)s %(name)s [-] %(instance)s%(message)s

# data to append to log format when level is DEBUG (string
# value)
# logging_debug_format_suffix=%(funcName)s %(pathname)s:%(lineno)d

# prefix each line of exception output with this format
# (string value)
# logging_exception_prefix=%(asctime)s.%(msecs)03d %(process)d TRACE %(name)s
# %(instance)s

# list of logger=LEVEL pairs (list value)
# default_log_levels=amqplib=WARN,sqlalchemy=WARN,boto=WARN,suds=INFO,
# keystone=INFO,eventlet.wsgi.server=WARNsages without context
# (string value)

# If an instance is passed with the log message, format it
# like this (string value)
# instance_format="[instance: %(uuid)s]"

# If an instance UUID is passed with the log message, format
# it like this (string value)
#instance_uuid_format="[instance: %(uuid)s] "

# Format string for %%(asctime)s in log records. Default:
# %(default)s (string value)
# log_date_format=%Y-%m-%d %H:%M:%S

# (Optional) Name of log file to output to. If not set,
# logging will go to stdout. (string value)
# log_file=<None>

# (Optional) The directory to keep log files in (will be
# prepended to --log-file) (string value)
# log_dir=<None>
# instance_uuid_format="[instance: %(uuid)s]"

# If this option is specified, the logging configuration file
# specified is used and overrides any other logging options
# specified. Please see the Python logging module
# documentation for details on logging configuration files.
# (string value)
# Use syslog for logging. (boolean value)
# use_syslog=false

# syslog facility to receive log lines (string value)
# syslog_log_facility=LOG_USER
# log_config=<None>

These common issues might occur during configuration, and the
following potential solutions describe how to address the issues.

Issues with
state_path and volumes_dir settings

Problem

The OpenStack Block Storage uses tgtd as the default
iSCSI helper and implements persistent targets. This means that in the
case of a tgt restart, or even a node reboot, your existing
volumes on that node will be restored automatically with their original
IQN <iSCSI
Qualified Name (IQN)>.

By default, Block Storage uses a state_path variable,
which if installing with Yum or APT should be set to
/var/lib/cinder/. The next part is the
volumes_dir variable, by default this appends a
volumes directory to the state_path. The
result is a file-tree: /var/lib/cinder/volumes/.

Solution

In order to ensure nodes are restored to their original IQN, the
iSCSI target information needs to be stored in a file on creation that
can be queried in case of restart of the tgt daemon. While
the installer should handle all this, it can go wrong.

If you have trouble creating volumes and this directory does not
exist you should see an error message in the cinder-volume
log indicating that the volumes_dir does not exist, and it
should provide information about which path it was looking for.

The persistent tgt include
file

Problem

The Block Storage service may have issues locating the persistent
tgt include file. Along with the volumes_dir
option, the iSCSI target driver also needs to be configured to look in
the correct place for the persistent tgt include file. This
is an entry in the /etc/tgt/conf.d file that should have
been set during the OpenStack installation.

Solution

If issues occur, verify that you have a
/etc/tgt/conf.d/cinder.conf file. If the file is not
present, create it with:

# echo 'include /var/lib/cinder/volumes/ *' >> /etc/tgt/conf.d/cinder.conf

Failed
to create iscsi target error in the cinder-volume.log
file

Problem

2013-03-12 01:35:43 1248 TRACE cinder.openstack.common.rpc.amqp \
ISCSITargetCreateFailed: \
Failed to create iscsi target for volume \
volume-137641b2-af72-4a2f-b243-65fdccd38780.

You might see this error in cinder-volume.log after
trying to create a volume that is 1 GB.

Solution

To fix this issue, change the content of the
/etc/tgt/targets.conf file from
include /etc/tgt/conf.d/*.conf to
include /etc/tgt/conf.d/cinder_tgt.conf, as follows:

include /etc/tgt/conf.d/cinder_tgt.conf
include /etc/tgt/conf.d/cinder.conf
default-driver iscsi

Restart tgt and cinder-* services, so they
pick up the new configuration.