It looks like juju is retrying a failed container provisioning with the same container name. Produced with the reproducer of 1950771. This is not the same as the logs provided a above.
2021-12-08 21:47:18 INFO juju.container.lxd container.go:255 starting new container "juju-d3dd2f-1-lxd-0" (image "ubuntu-16.04-server-cloudimg-amd64-lxd.tar.xz")
2021-12-08 21:49:32 WARNING juju.worker.provisioner provisioner_task.go:1114 machine 1/lxd/0 failed to start: websocket: close 1006 (abnormal closure): unexpected EOF
2021-12-08 21:49:32 WARNING juju.worker.provisioner provisioner_task.go:1153 failed to start machine 1/lxd/0 (websocket: close 1006 (abnormal closure): unexpected EOF), retrying in 10s (10 more attempts)
2021-12-08 21:49:42 WARNING juju.container.broker broker.go:76 no name servers supplied by provider, using host's name servers.
2021-12-08 21:49:42 WARNING juju.container.broker broker.go:76 no search domains supplied by provider, using host's search domains.
2021-12-08 21:49:42 WARNING juju.container.broker broker.go:84 incomplete DNS config found, discovering host's DNS config
2021-12-08 21:49:45 WARNING juju.container.lxd manager.go:200 no CIDR was detected for the following networks: [fan-253]
2021-12-08 21:49:46 INFO juju.cloudconfig userdatacfg_unix.go:575 Fetching agent: curl -sSfw 'agent binaries from %{url_effective} downloaded: HTTP %{http_code}; time %{time_total}s; size %{size_download} bytes; speed %{speed_download} bytes/s ' --connect-timeout 20 --noproxy "*" --insecure -o $bin/tools.tar.gz <[https://10.240.0.58:17070/model/228ded55-1a5a-4d21-8f6a-2be9c5d3dd2f/tools/2.9.18-ubuntu-amd64https://253.0.58.1:17070/model/228ded55-1a5a-4d21-8f6a-2be9c5d3dd2f/tools/2.9.18-ubuntu-amd64https://35.237.242.119:17070/model/228ded55-1a5a-4d21-8f6a-2be9c5d3dd2f/tools/2.9.18-ubuntu-amd64]>
2021-12-08 21:49:47 INFO juju.container.lxd container.go:255 starting new container "juju-d3dd2f-1-lxd-0" (image "ubuntu-16.04-server-cloudimg-amd64-lxd.tar.xz")
2021-12-08 21:49:49 WARNING juju.worker.provisioner provisioner_task.go:1114 machine 1/lxd/0 failed to start: Failed creating instance record: Add instance info to the database: This instance already exists
New info: "websocket: close 1006 (abnormal closure): unexpected EOF" tends to happen if the host machine is created with only 1G of memory. As do other container problems. Using a memory constraint of 4G does not reproduce the websocket failure.
It looks like juju is retrying a failed container provisioning with the same container name. Produced with the reproducer of 1950771. This is not the same as the logs provided a above.
2021-12-08 21:47:18 INFO juju.container.lxd container.go:255 starting new container "juju-d3dd2f- 1-lxd-0" (image "ubuntu- 16.04-server- cloudimg- amd64-lxd. tar.xz" ) provisioner provisioner_ task.go: 1114 machine 1/lxd/0 failed to start: websocket: close 1006 (abnormal closure): unexpected EOF provisioner provisioner_ task.go: 1153 failed to start machine 1/lxd/0 (websocket: close 1006 (abnormal closure): unexpected EOF), retrying in 10s (10 more attempts) broker broker.go:76 no name servers supplied by provider, using host's name servers. broker broker.go:76 no search domains supplied by provider, using host's search domains. broker broker.go:84 incomplete DNS config found, discovering host's DNS config unix.go: 575 Fetching agent: curl -sSfw 'agent binaries from %{url_effective} downloaded: HTTP %{http_code}; time %{time_total}s; size %{size_download} bytes; speed %{speed_download} bytes/s ' --connect-timeout 20 --noproxy "*" --insecure -o $bin/tools.tar.gz <[https:/ /10.240. 0.58:17070/ model/228ded55- 1a5a-4d21- 8f6a-2be9c5d3dd 2f/tools/ 2.9.18- ubuntu- amd64 https:/ /253.0. 58.1:17070/ model/228ded55- 1a5a-4d21- 8f6a-2be9c5d3dd 2f/tools/ 2.9.18- ubuntu- amd64 https:/ /35.237. 242.119: 17070/model/ 228ded55- 1a5a-4d21- 8f6a-2be9c5d3dd 2f/tools/ 2.9.18- ubuntu- amd64]> 1-lxd-0" (image "ubuntu- 16.04-server- cloudimg- amd64-lxd. tar.xz" ) provisioner provisioner_ task.go: 1114 machine 1/lxd/0 failed to start: Failed creating instance record: Add instance info to the database: This instance already exists
2021-12-08 21:49:32 WARNING juju.worker.
2021-12-08 21:49:32 WARNING juju.worker.
2021-12-08 21:49:42 WARNING juju.container.
2021-12-08 21:49:42 WARNING juju.container.
2021-12-08 21:49:42 WARNING juju.container.
2021-12-08 21:49:45 WARNING juju.container.lxd manager.go:200 no CIDR was detected for the following networks: [fan-253]
2021-12-08 21:49:46 INFO juju.cloudconfig userdatacfg_
2021-12-08 21:49:47 INFO juju.container.lxd container.go:255 starting new container "juju-d3dd2f-
2021-12-08 21:49:49 WARNING juju.worker.
New info: "websocket: close 1006 (abnormal closure): unexpected EOF" tends to happen if the host machine is created with only 1G of memory. As do other container problems. Using a memory constraint of 4G does not reproduce the websocket failure.