# Use of Nested Variables **URL:** \ **Category:** Ansible Project\ **Created:** [February 16, 2021, 1:24pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629 "2021-02-16T13:24:19Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 16, 2021, 1:24pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/1 "2021-02-16T13:24:19Z")
# Goal: When playbook / task is called.. use varibles set for specific host withing a group /hosts.yml # site wide master ansible inentory all: children: ###### Physical HyperConverge Server Devices for environment hci\_hosts: # Nodes for hosting VMs hosts: thor: vars: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: ens15f0 ovs\_nic: enp8s0f1 ovirt\_disk: ata-Samsung\_SSD\_850\_PRO\_512GB\_S250NXAGA15787L # ls -al /dev/disk/by-id/ |grep sdb data00\_disk: ata-WDC\_WDS100T2B0B-00YS70\_192490801828 # ls -al /dev/disk/by-id/ |grep sdc data01\_disk: ata-WDC\_WDS100T2B0B-00YS70\_19106A802926 # ls -al /dev/disk/by-id/ |grep sdd odin: vars: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: ens15f0 ovirt\_disk: ata-Micron\_1100\_MTFDDAV512TBN\_17401F699137 # ls -al /dev/disk/by-id/ |grep sdb data00\_disk: ata-WDC\_WDS100T2B0B-00YS70\_183533804564 # ls -al /dev/disk/by-id/ |grep sdc data01\_disk: nvme-nvme.126f-4141303030303030303030303030303032343538-53504343204d2e32205043496520535344-00000001 # ls -al /dev/disk/by-id/ |grep nvme0n1 … #### Task: setup host networking and disk.. where each host is different .. so have to set individulized varibles ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 1:36pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/2 "2021-02-17T13:36:53Z")
Any idea or help here I see this concept is valid.[https://docs.ansible.com/ansible/latest/user\_guide/playbooks\_variables.html#referencing-nested-variables](https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html#referencing-nested-variables) But for above example: - debug: # this works to set variable for storage interface [https://docs.ansible.com/ansible/latest/collections/community/general/nmcli\_module.html](https://docs.ansible.com/ansible/latest/collections/community/general/nmcli_module.html) msg: “‘{{ inventory\_hostname }}s’ this should be hostname with s added such as thors” - debug: msg: “{{ inventory\_hostname }} this should be hostname response of thor” - debug: msg: “{{ inventory\_hostname.storage\_nic }} this should be response of ens15f0” - debug: msg: “{{ ansible\_facts.storage\_nic }} I guess if ansible\_fact is a special ansible variable…this should be hostname response of ens15f0” \<\< output\> /cluster\_devops$ ansible-playbook hci\_deploy.yml --limit thor PLAY [Ansible Pinging Host which validates SSH passwordless login] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* TASK [Gathering Facts] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*ok: [thor] TASK [hci\_cluster : Copy a version of hosts file common for nodes to ignite cluster] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*ok: [thor] TASK [hci\_cluster : debug] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*ok: [thor] =\> msg: ‘’‘thors’’ this should be hostname with s added such as thors’ TASK [hci\_cluster : debug] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*ok: [thor] =\> msg: thor this should be hostname response of thor TASK [hci\_cluster : debug] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*fatal: [thor]: FAILED! =\> msg: |- The task includes an option with an undefined variable. The error was: ‘ansible.parsing.yaml.objects.AnsibleUnicode object’ has no attribute ‘storage\_nic’ The error appears to be in ‘/mnt/c/GitHub/penguinpages\_cluster\_devops/cluster\_devops/roles/task\_network\_hosts.yml’: line 63, column 3, but may be elsewhere in the file depending on the exact syntax problem. The offending line appears to be: msg: “{{ inventory\_hostname }} this should be hostname response of thor” - debug: ^ here PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*thor : ok=4 changed=0 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0 ---
**Author:** ![racke](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/racke/32/4767_2.png) [@racke](https://forum.ansible.com/u/racke)\ **Post date:** [February 17, 2021, 2:06pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/3 "2021-02-17T14:06:46Z")
> Any idea or help here > > I see this concept is > valid.[https://docs.ansible.com/ansible/latest/user\_guide/playbooks\_variables.html#referencing-nested-variables](https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html#referencing-nested-variables) > > But for above example: > > - debug: # this works to set variable for storage interface [https://docs.ansible.com/ansible/latest/collections/community/general/nmcli\_module.html](https://docs.ansible.com/ansible/latest/collections/community/general/nmcli_module.html) > msg: "'{{ inventory\_hostname }}s' this should be hostname with s added such as thors" > - debug: > msg: "{{ inventory\_hostname }} this should be hostname response of thor" > - debug: > msg: "{{ inventory\_hostname.storage\_nic }} this should be response of ens15f0" > - debug: > msg: "{{ ansible\_facts.storage\_nic }} I guess if ansible\_fact is a special ansible variable...this should be hostname response of ens15f0" You don't show the task which uses nmlci\_module and provides storage\_nic information. inventory\_hostname.storage\_nic is totally bogus as a string can't be a nested variable. Regards          Racke ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 2:55pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/4 "2021-02-17T14:55:47Z")
Well. I was trying to keep it simple and just validate the variable call was valid before trying to use it in a task. But task would be something along lines of: - name: Get server storage IP address from /etc/hosts command: “grep ‘{{ inventory\_hostname }}s’ /etc/hosts | awk ‘{ print $1 }’” register: storage\_ip - task: # Set Storage IP for host nmci: ipaddress: {{storage\_ip}} interface: {{ inventory\_hostname.storage\_nic }} mask: 24 mtu: 9000 That is the hope it will work. ---
**Author:** ![racke](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/racke/32/4767_2.png) [@racke](https://forum.ansible.com/u/racke)\ **Post date:** [February 17, 2021, 3:03pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/5 "2021-02-17T15:03:57Z")
> Well. I was trying to keep it simple and just validate the variable call was valid before trying to use it in a task. > > But task would be something along lines of: > - name: Get server storage IP address from /etc/hosts > command: "grep '{{ inventory\_hostname }}s' /etc/hosts | awk '{ print $1 }'" > register: storage\_ip So the result of the command is stored in the variable storage\_ip and the output of the command is stored in storage\_ip.stdout (as string) and storage\_ip.stdout\_lines (list of output lines). To show the result: debug:    var: storage\_ip > - task: # Set Storage IP for host > nmci: > ipaddress: {{storage\_ip}} > interface: {{ inventory\_hostname.storage\_nic }} > mask: 24 > mtu: 9000 So ipaddress might be {{ storage\_ip.stdout }} Regards          Racke ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 3:45pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/6 "2021-02-17T15:45:09Z")
My issue is not getting the variable set of “storage\_ip” But that I have to define variables in the global inventory file… That are unique to each host. And when I run a playbook and it needs those variables… how do I get them. Ex: When I want to run a playbook for group “hci\_cluster” which then runs on three hosts… First host is “thor” It has its 10Gb storage NIC as enp8s0f1 so when the playbook is running. use variable “hci\_cluster-\> thor-\>storage\_nic” to know to bind ip to enp8s0f1 But how do I use a nested variable ? ---
**Author:** ![racke](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/racke/32/4767_2.png) [@racke](https://forum.ansible.com/u/racke)\ **Post date:** [February 17, 2021, 4:05pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/7 "2021-02-17T16:05:04Z")
> My issue is not getting the variable set of "storage\_ip" > > But that I have to define variables in the global inventory file.. That are unique to each host. > > And when I run a playbook and it needs those variables.. how do I get them. > > Ex: > > When I want to run a playbook for group "hci\_cluster" which then runs on three hosts.. > > First host is "thor" > It has its 10Gb storage NIC as enp8s0f1 > > so when the playbook is running. use variable "hci\_cluster-\> thor-\>storage\_nic" to know to bind ip to enp8s0f1 > > But how do I use a nested variable ? You don't need it. It should be present as "storage\_nic" variable given your inventory: hosts:   thor:     vars:       mgmt\_nic: enp8s0f0 # Set in Kickstart OS install       storage\_nic: ens15f0       ovs\_nic: enp8s0f1 So please try to use {{ storage\_nic }}. Regards         Racke ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 6:03pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/8 "2021-02-17T18:03:53Z")
I 100% agree with you. If I set a host variable … that should be read and take precedence from what I am reading. …but that in lies the issue… it does not work… ---
**Author:** ![racke](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/racke/32/4767_2.png) [@racke](https://forum.ansible.com/u/racke)\ **Post date:** [February 17, 2021, 6:10pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/9 "2021-02-17T18:10:46Z")
> I 100% agree with you. If I set a host variable ... that should be read and take precedence from what I am reading. > > ....but that in lies the issue.. it does not work.... This causes the error: - debug:     msg: "{{ inventory\_hostname.{{ storage\_nic }} }} this should be NIC of thor for storage" So you never reached: - debug:     msg: "{{ storage\_nic }} this should be NIC of thor for storage" You really need to try to understand what the error message clearly tells you. Regards         Racke ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 6:15pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/10 "2021-02-17T18:15:37Z")
Ok.. same inventory file: ## one task.. - debug: msg: “{{ storage\_nic }} this should be NIC of thor for storage” ## output cluster\_devops$ ansible-playbook hci\_deploy.yml --limit thor PLAY [Ansible Pinging Host which validates SSH passwordless login] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\* TASK [Gathering Facts] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*ok: [thor] TASK [hci\_cluster : debug] \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*fatal: [thor]: FAILED! =\> msg: |- The task includes an option with an undefined variable. The error was: ‘storage\_nic’ is undefined The error appears to be in ‘/mnt/c/GitHub/penguinpages\_cluster\_devops/cluster\_devops/roles/task\_network\_hosts.yml’: line 78, column 3, but may be elsewhere in the file depending on the exact syntax problem. The offending line appears to be: # msg: “{{ inventory\_hostname[storage\_nic] }} this should be NIC of thor for storage” - debug: ^ here PLAY RECAP \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*thor : ok=1 changed=0 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0 ---
**Author:** ![racke](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/racke/32/4767_2.png) [@racke](https://forum.ansible.com/u/racke)\ **Post date:** [February 17, 2021, 7:31pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/11 "2021-02-17T19:31:37Z")
> Ok.. same inventory file: > > ## one task.. > - debug: > msg: "{{ storage\_nic }} this should be NIC of thor for storage" Please remove vars: from your inventory and run your task again. hci\_hosts: # Nodes for hosting VMs   hosts:     thor:       mgmt\_nic: enp8s0f0 # Set in Kickstart OS install       storage\_nic: ens15f0 Regards        Racke ---
**Author:** ![penguinpages](https://sea1.discourse-cdn.com/ansible/user_avatar/forum.ansible.com/penguinpages/32/8179_2.png) [@penguinpages](https://forum.ansible.com/u/penguinpages)\ **Post date:** [February 17, 2021, 9:01pm UTC](https://forum.ansible.com/t/use-of-nested-variables/34629/12 "2021-02-17T21:01:55Z")
That was it!!! Root cause: Stanza of “var:” though valid.. and used by some in examples.. is NOT valid. ######Good: no “var” for hosts section but must have var for group… all: children: ###### Physical HyperConverge Server Devices for environment hci\_hosts: # Nodes for hosting VMs hosts: thor: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: ens15f0 ovs\_nic: enp8s0f1 odin: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: enp7s0f1 vars: ansible\_ssh\_pass: “{{ vault\_ansible\_sudo\_password }}” thor\_storage\_nic: ens15f0 ###### bad use of var: under host hci\_hosts: # Nodes for hosting VMs hosts: thor: var: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: ens15f0 ovs\_nic: enp8s0f1 odin: var: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: enp7s0f1 vars: ansible\_ssh\_pass: “{{ vault\_ansible\_sudo\_password }}” thor\_storage\_nic: ens15f0 ############### BAD removal of var: from hci\_cluster group hci\_hosts: # Nodes for hosting VMs hosts: thor: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: ens15f0 ovs\_nic: enp8s0f1 odin: mgmt\_nic: enp8s0f0 # Set in Kickstart OS install storage\_nic: enp7s0f1 ansible\_ssh\_pass: “{{ vault\_ansible\_sudo\_password }}” thor\_storage\_nic: ens15f0 Meh… it works… don’t ask me 😛 Thanks for postings.