7a6334e4bc
Each datasource had a bit of doc with it, and those were just landing in doc/. I've moved them to doc/sources now.
119 lines
4.4 KiB
Plaintext
119 lines
4.4 KiB
Plaintext
The 'ConfigDrive' DataSource supports the OpenStack configdrive disk.
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See doc/source/api_ext/ext_config_drive.rst in the nova source code for
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more information on config drive.
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The following criteria are required to be identified by
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DataSourceConfigDrive as a config drive:
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* must be formated with vfat filesystem
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* must be a un-partitioned block device (/dev/vdb, not /dev/vdb1)
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* must contain one of the following files:
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* etc/network/interfaces
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* root/.ssh/authorized_keys
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* meta.js
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By default, cloud-init does not consider this source to be a full-fledged
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datasource. Instead, the default behavior is to assume it is really only
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present to provide networking information. Cloud-init will copy off the
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network information, apply it to the system, and then continue on. The
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"full" datasource would then be found in the EC2 metadata service.
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== Content of config-drive ==
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* etc/network/interfaces
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This file is laid down by nova in order to pass static networking
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information to the guest. Cloud-init will copy it off of the config-drive
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and into /etc/network/interfaces as soon as it can, and then attempt to
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bring up all network interfaces.
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* root/.ssh/authorized_keys
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This file is laid down by nova, and contains the keys that were
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provided to it on instance creation (nova-boot --key ....)
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Cloud-init will copy those keys and put them into the configured user
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('ubuntu') .ssh/authorized_keys.
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* meta.js
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meta.js is populated on the config-drive in response to the user passing
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"meta flags" (nova boot --meta key=value ...). It is expected to be json
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formated.
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== Configuration ==
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Cloud-init's behavior can be modified by keys found in the meta.js file in
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the following ways:
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* dsmode:
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values: local, net, pass
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default: pass
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This is what indicates if configdrive is a final data source or not.
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By default it is 'pass', meaning this datasource should not be read.
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Set it to 'local' or 'net' to stop cloud-init from continuing on to
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search for other data sources after network config.
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The difference between 'local' and 'net' is that local will not require
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networking to be up before user-data actions (or boothooks) are run.
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* instance-id:
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default: iid-dsconfigdrive
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This is utilized as the metadata's instance-id. It should generally
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be unique, as it is what is used to determine "is this a new instance".
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* public-keys:
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default: None
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if present, these keys will be used as the public keys for the
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instance. This value overrides the content in authorized_keys.
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Note: it is likely preferable to provide keys via user-data
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* user-data:
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default: None
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This provides cloud-init user-data. See other documentation for what
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all can be present here.
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== Example ==
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Here is an example using the nova client (python-novaclien)
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Assuming the following variables set up:
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* img_id : set to the nova image id (uuid from image-list)
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* flav_id : set to numeric flavor_id (nova flavor-list)
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* keyname : set to name of key for this instance (nova keypair-list)
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$ cat my-user-data
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#!/bin/sh
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echo ==== USER_DATA FROM EC2 MD ==== | tee /ud.log
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$ ud_value=$(sed 's,EC2 MD,META KEY,')
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## Now, 'ud_value' has same content of my-user-data file, but
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## with the string "USER_DATA FROM META KEY"
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## launch an instance with dsmode=pass
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## This will really not use the configdrive for anything as the mode
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## for the datasource is 'pass', meaning it will still expect some
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## other data source (DataSourceEc2).
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$ nova boot --image=$img_id --config-drive=1 --flavor=$flav_id \
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--key_name=$keyname \
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--user_data=my-user-data \
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"--meta=instance-id=iid-001 \
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"--meta=user-data=${ud_keyval}" \
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"--meta=dsmode=pass" cfgdrive-dsmode-pass
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$ euca-get-console-output i-0000001 | grep USER_DATA
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echo ==== USER_DATA FROM EC2 MD ==== | tee /ud.log
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## Now, launch an instance with dsmode=local
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## This time, the only metadata and userdata available to cloud-init
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## are on the config-drive
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$ nova boot --image=$img_id --config-drive=1 --flavor=$flav_id \
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--key_name=$keyname \
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--user_data=my-user-data \
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"--meta=instance-id=iid-001 \
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"--meta=user-data=${ud_keyval}" \
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"--meta=dsmode=local" cfgdrive-dsmode-local
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$ euca-get-console-output i-0000002 | grep USER_DATA
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echo ==== USER_DATA FROM META KEY ==== | tee /ud.log
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--
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[1] https://github.com/openstack/nova/blob/master/doc/source/api_ext/ext_config_drive.rst for more if
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