Hi Christopher,
Am trying to work on something where the listdisks module can perfectly
fit, do you mind sharing the code for listdisks module?
On Friday, January 17, 2014 at 1:33:18 PM UTC-8, Christopher O'Connell
wrote:
>
> Hello List,
>
> I understand that a decision has been made to remove include + with_items,
> and I am not trying to directly revisit that decision. What I am trying to
> figure out is how to effectively replace such constructs in our roles. If
> someone reads this and concludes that I'm approaching my problem entirely
> wrong, then please pipe up and let me know I'm an idiot.
>
> Consider a custom module called "listdisks" which (as the name suggests),
> lists information about the physical disks installed in a system (whether
> they're formatted and mounted, or not). Example output:
>
> {
> "changed": false,
> "drives": [
> {
> "hasPartitions": true,
> "name": "sda",
> "partitions": [
> {
> "filesystem": "ext3",
> "mount": "/boot",
> "name": "1",
> "size": "268",
> "sizeUnits": "MB"
> },
> {
> "filesystem": "linux-swap",
> "mount": null,
> "name": "2",
> "size": "8590",
> "sizeUnits": "MB"
> },
> {
> "filesystem": "ext4",
> "mount": "/",
> "name": "3",
> "size": "111",
> "sizeUnits": "GB"
> }
> ],
> "size": "120",
> "sizeUnits": "GB"
> },
> {
> "hasPartitions": false,
> "name": "sdb",
> "partitions": [],
> "size": "2000",
> "sizeUnits": "GB"
> }
> ],
> "item":""
> }
>
> As a simple example of the problem, consider a playbook to simply print a
> debug message for each existing partition which does not have an identified
> mount point.
>
> This playbook snippet works without using include or with_items:
>
> - name: get outstanding drives
> listdisks: unpartitioned=true
> register: system_disks
> - name: identify unmounted partitions
> debug: msg="/dev/{{ item[0].name }}{{ item[1].name }} ({{ item[1].size
> }}{{ item[1].sizeUnits }}) not mounted"
> when: item[0].hasPartitions == True and item[1].mount == None
> with_subelements:
> - system_disks.drives
> - partitions
>
> Sample output (with some specific domain name information elided):
>
> PLAY [configure ceph systems]
> *************************************************
>
> GATHERING FACTS
> ***************************************************************
> ok: [system1232]
> ok: [system1233]
> ok: [system1234]
>
> TASK: [ceph | get outstanding drives]
> *****************************************
> ok: [system1233]
> ok: [system1232]
> ok: [system1234]
>
> TASK: [ceph | identify unmounted partitions]
> **********************************
> skipping: [system1233] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount':
> u'/boot', u'size': u'268', u'name': u'1', u'filesystem': u'ext3'}))
> skipping: [system1232] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount':
> u'/boot', u'size': u'268', u'name': u'1', u'filesystem': u'ext3'}))
> skipping: [system1234] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount':
> u'/boot', u'size': u'268', u'name': u'1', u'filesystem': u'ext3'}))
> ok: [system1233] => (item=({u'hasPartitions': True, u'sizeUnits': u'GB',
> u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount': None,
> u'size': u'8590', u'name': u'2', u'filesystem': u'linux-swap'})) => {
> "item": [
> {
> "hasPartitions": true,
> "name": "sda",
> "size": "120",
> "sizeUnits": "GB"
> },
> {
> "filesystem": "linux-swap",
> "mount": null,
> "name": "2",
> "size": "8590",
> "sizeUnits": "MB"
> }
> ],
> "msg": "/dev/sda2 (8590MB) not mounted"
> }
> ok: [system1232] => (item=({u'hasPartitions': True, u'sizeUnits': u'GB',
> u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount': None,
> u'size': u'8590', u'name': u'2', u'filesystem': u'linux-swap'})) => {
> "item": [
> {
> "hasPartitions": true,
> "name": "sda",
> "size": "120",
> "sizeUnits": "GB"
> },
> {
> "filesystem": "linux-swap",
> "mount": null,
> "name": "2",
> "size": "8590",
> "sizeUnits": "MB"
> }
> ],
> "msg": "/dev/sda2 (8590MB) not mounted"
> }
> skipping: [system1233] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'GB', u'mount':
> u'/', u'size': u'111', u'name': u'3', u'filesystem': u'ext4'}))
> ok: [system1234] => (item=({u'hasPartitions': True, u'sizeUnits': u'GB',
> u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'MB', u'mount': None,
> u'size': u'8590', u'name': u'2', u'filesystem': u'linux-swap'})) => {
> "item": [
> {
> "hasPartitions": true,
> "name": "sda",
> "size": "120",
> "sizeUnits": "GB"
> },
> {
> "filesystem": "linux-swap",
> "mount": null,
> "name": "2",
> "size": "8590",
> "sizeUnits": "MB"
> }
> ],
> "msg": "/dev/sda2 (8590MB) not mounted"
> }
> skipping: [system1232] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'GB', u'mount':
> u'/', u'size': u'111', u'name': u'3', u'filesystem': u'ext4'}))
> skipping: [system1234] => (item=({u'hasPartitions': True, u'sizeUnits':
> u'GB', u'size': u'120', u'name': u'sda'}, {u'sizeUnits': u'GB', u'mount':
> u'/', u'size': u'111', u'name': u'3', u'filesystem': u'ext4'}))
>
> PLAY RECAP
> ********************************************************************
> system1232 : ok=3 changed=0 unreachable=0 failed=0
> system1233 : ok=3 changed=0 unreachable=0 failed=0
> system1234 : ok=3 changed=0 unreachable=0 failed=0
>
> This playbook works perfectly. The problem is that it is virtually
> unreadable. Take a look at just the command to debug information about the
> unmounted drives:
>
> debug: msg="/dev/{{ item[0].name }}{{ item[1].name }} ({{ item[1].size
> }}{{ item[1].sizeUnits }}) not mounted"
> when: item[0].hasPartitions == True and item[1].mount == None
> with_subelements:
> - system_disks.drives
> - partitions
>
> Simply looking at that command makes very little sense of what it actually
> does. Furthermore, the when and with_subelements clauses must be repeated
> for every single item in a long role. In the role I've drawn this example
> from, I need to partition, format and mount drives newly connected (or
> reconnected after a drive replacement) to the system and then inform the
> ceph agent about these devices. At the moment I have about 14 tasks with
> the ugly when + with_subelements clauses. This wildly violates the
> principle of "Don't Repeat Yourself", and not just in an abstract way --
> the impetus to write this email came after spending nearly 4 hours tracking
> down a typo in a single one of these repeated clauses. Surely there must be
> a better way, either already baked into Ansible, or if not, then added to
> the road map.
>
> On a related note, since updating to the 1.5 working branch, I've noticed
> a regression using include + when where some of the included tasks also
> have a when clause. Based on reading this closed bug [
> https://github.com/ansible/ansible/issues/3269] it appears that include +
> when and an inner when clause should work, but I have not found this to
> be the case. I haven't spent considerable time trying to debug this since
> I'm moving away from using include at all and towards really long roles,
> but if this behavior is being intentionally removed, some documentation
> seems like a good idea.
>
> All the best,
>
> ~ Christopher
>
> P.S. If the listdisks module seems like something of interest, I'll
> consider adding it to the ansible-galaxy thingy.
>
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