Charmed MySQL

Channel Revision Published Runs on
8.0/stable 240 20 Jun 2024
Ubuntu 22.04
8.0/candidate 297 15 Oct 2024
Ubuntu 22.04
8.0/candidate 296 15 Oct 2024
Ubuntu 22.04
8.0/beta 297 07 Oct 2024
Ubuntu 22.04
8.0/beta 296 07 Oct 2024
Ubuntu 22.04
8.0/edge 303 09 Oct 2024
Ubuntu 22.04
8.0/edge 302 09 Oct 2024
Ubuntu 22.04
juju deploy mysql --channel 8.0/edge
Show information

Platform:

Ubuntu
22.04

Deploy on multiple availability zones (AZ)

During the deployment to hardware/VMs, it is important to spread all the database copies (Juju units) to different hardware servers, or even better, to the different availability zones (AZ). This will guarantee no shared service-critical components across the DB cluster (eliminate the case with all eggs in the same basket).

This guide will take you through deploying a MySQL cluster on GCE using 3 available zones. All Juju units will be set up to sit in their dedicated zones only, which effectively guarantees database copy survival across all available AZs.

This documentation assumes that your cloud supports and provides availability zones concepts. This is enabled by default on EC2/GCE and supported by LXD/MicroCloud.

See the Additional resources section for more details about AZ on specific clouds.

Summary


Set up GCE on Google Cloud

Let’s deploy the MySQL Cluster on GKE (us-east4) using all 3 zones there (us-east4-a, us-east4-b, us-east4-c) and make sure all pods always sits in the dedicated zones only.

Warning: Creating the following GKE resources may cost you money - be sure to monitor your GCloud costs.

Log into Google Cloud and bootstrap GCE on Google Cloud:

gcloud auth login
gcloud iam service-accounts keys create sa-private-key.json  --iam-account=juju-gce-account@[your-gcloud-project-12345].iam.gserviceaccount.com
sudo mv sa-private-key.json /var/snap/juju/common/sa-private-key.json
sudo chmod a+r /var/snap/juju/common/sa-private-key.json

juju add-credential google
juju bootstrap google gce
juju add-model mymodel

Deploy MySQL with Juju zones constraints

Juju provides the support for availability zones using constraints. Read more about zones in Juju documentation.

The command below demonstrates how Juju automatically deploys Charmed MySQL VM using Juju constraints:

juju deploy mysql -n 3 \
  --constraints zones=us-east1-b,us-east1-c,us-east1-d

After a successful deployment, juju status will show an active application:

Model    Controller  Cloud/Region     Version    SLA          Timestamp
mymodel  gce         google/us-east1  3.6-rc1.1  unsupported  00:59:53+02:00

App    Version          Status  Scale  Charm  Channel     Rev  Exposed  Message
mysql  8.0.36-0ubun...  active      3  mysql  8.0/stable  240  no       

Unit      Workload  Agent  Machine  Public address  Ports           Message
mysql/0   active    idle   0        34.23.202.220   3306,33060/tcp  
mysql/1*  active    idle   1        34.148.44.51    3306,33060/tcp  Primary
mysql/2   active    idle   2        34.23.252.144   3306,33060/tcp  

Machine  State    Address        Inst id        Base          AZ          Message
0        started  34.23.202.220  juju-5fe1b7-0  ubuntu@22.04  us-east1-c  RUNNING
1        started  34.148.44.51   juju-5fe1b7-1  ubuntu@22.04  us-east1-d  RUNNING
2        started  34.23.252.144  juju-5fe1b7-2  ubuntu@22.04  us-east1-b  RUNNING

and each unit/vm will sit in the separate AZ out of the box:

> gcloud compute instances list

NAME           ZONE        MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP    STATUS
juju-5fe1b7-2  us-east1-b  e2-highcpu-2               10.142.0.38  34.23.252.144  RUNNING  # mysql/2
juju-81e41f-0  us-east1-b  n1-highcpu-4               10.142.0.35  34.138.167.85  RUNNING  # Juju Controller
juju-5fe1b7-0  us-east1-c  e2-highcpu-2               10.142.0.36  34.23.202.220  RUNNING  # mysql/0
juju-5fe1b7-1  us-east1-d  e2-highcpu-2               10.142.0.37  34.148.44.51   RUNNING  # mysql/1

Simulation: A node gets lost

Let’s destroy a GCE node and recreate it using the same AZ (Primary MySQL unit is being removed):

> gcloud compute instances delete juju-5fe1b7-1
No zone specified. Using zone [us-east1-d] for instance: [juju-5fe1b7-1].
The following instances will be deleted. Any attached disks configured to be auto-deleted will be deleted unless they are attached to any other instances or the `--keep-disks` flag is given and specifies them for keeping. Deleting a disk is 
irreversible and any data on the disk will be lost.
 - [juju-5fe1b7-1] in [us-east1-d]

Do you want to continue (Y/n)?  Y

Deleted [https://www.googleapis.com/compute/v1/projects/data-platform-testing-354909/zones/us-east1-d/instances/juju-5fe1b7-1].

The new MySQL Primary elected automatically:

Model    Controller  Cloud/Region     Version    SLA          Timestamp
mymodel  gce         google/us-east1  3.6-rc1.1  unsupported  01:03:13+02:00

App    Version          Status  Scale  Charm  Channel     Rev  Exposed  Message
mysql  8.0.36-0ubun...  active    2/3  mysql  8.0/stable  240  no       

Unit      Workload  Agent  Machine  Public address  Ports           Message
mysql/0*  active    idle   0        34.23.202.220   3306,33060/tcp  Primary
mysql/1   unknown   lost   1        34.148.44.51    3306,33060/tcp  agent lost, see 'juju show-status-log mysql/1'
mysql/2   active    idle   2        34.23.252.144   3306,33060/tcp  

Machine  State    Address        Inst id        Base          AZ          Message
0        started  34.23.202.220  juju-5fe1b7-0  ubuntu@22.04  us-east1-c  RUNNING
1        down     34.148.44.51   juju-5fe1b7-1  ubuntu@22.04  us-east1-d  RUNNING
2        started  34.23.252.144  juju-5fe1b7-2  ubuntu@22.04  us-east1-b  RUNNING

Here we should remove the no longer available server/vm/GCE node and add a new one. Juju will create it in the same AZ us-east4-c:

> juju remove-unit mysql/1 --force --no-wait --no-prompt
WARNING This command will perform the following actions:
will remove unit mysql/1

The command juju status shows the machines in a healthy state, but MySQL HA recovery is necessary:

Model    Controller  Cloud/Region     Version    SLA          Timestamp
mymodel  gce         google/us-east1  3.6-rc1.1  unsupported  01:04:42+02:00

App    Version          Status  Scale  Charm  Channel     Rev  Exposed  Message
mysql  8.0.36-0ubun...  active      2  mysql  8.0/stable  240  no       

Unit      Workload  Agent  Machine  Public address  Ports           Message
mysql/0*  active    idle   0        34.23.202.220   3306,33060/tcp  Primary
mysql/2   active    idle   2        34.23.252.144   3306,33060/tcp  

Machine  State    Address        Inst id        Base          AZ          Message
0        started  34.23.202.220  juju-5fe1b7-0  ubuntu@22.04  us-east1-c  RUNNING
2        started  34.23.252.144  juju-5fe1b7-2  ubuntu@22.04  us-east1-b  RUNNING

Request Juju to add a new unit in the proper AZ:

juju add-unit mysql -n 1

Juju uses the right AZ where the node is missing. Run juju status:

Model    Controller  Cloud/Region     Version    SLA          Timestamp
mymodel  gce         google/us-east1  3.6-rc1.1  unsupported  01:05:12+02:00

App    Version  Status  Scale  Charm  Channel     Rev  Exposed  Message
mysql           active    2/3  mysql  8.0/stable  240  no       

Unit      Workload  Agent       Machine  Public address  Ports           Message
mysql/0*  active    idle        0        34.23.202.220   3306,33060/tcp  Primary
mysql/2   active    idle        2        34.23.252.144   3306,33060/tcp  
mysql/3   waiting   allocating  3                                        waiting for machine

Machine  State    Address        Inst id        Base          AZ          Message
0        started  34.23.202.220  juju-5fe1b7-0  ubuntu@22.04  us-east1-c  RUNNING
2        started  34.23.252.144  juju-5fe1b7-2  ubuntu@22.04  us-east1-b  RUNNING
3        pending                 juju-5fe1b7-3  ubuntu@22.04  us-east1-d  starting

Remove GCE setup

Warning: Do not forget to remove your test setup - it can be costly!

Check the list of currently running GCE instances:

> gcloud compute instances list
NAME           ZONE        MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP    STATUS
juju-5fe1b7-2  us-east1-b  e2-highcpu-2               10.142.0.38  34.23.252.144  RUNNING
juju-81e41f-0  us-east1-b  n1-highcpu-4               10.142.0.35  34.138.167.85  RUNNING
juju-5fe1b7-0  us-east1-c  e2-highcpu-2               10.142.0.36  34.23.202.220  RUNNING
juju-5fe1b7-3  us-east1-d  e2-highcpu-2               10.142.0.39  34.148.44.51   RUNNING

Request Juju to clean all GCE resources:

juju destroy-controller gce --no-prompt --force --destroy-all-models

Re-check that there are no running GCE instances left (it should be empty):

gcloud compute instances list