Enable profiling with Parca¶
This guide contains the steps to enable profiling with Parca for your PostgreSQL application.
Important
Read the Prerequisites section carefully if you are deploying PostgreSQL in an LXD model or if your base is ubuntu@22.04.
Prerequisites¶
A juju model with Charmed PostgreSQL deployed.
If you are using an LXD model, LXD’s virtualisation type must be set to
virtual-machine.See LXD virtualisation type for more details.
If your base is
ubuntu@22.4, you must use thegenericflavour of Linux.See Base (Ubuntu version) for more details.
LXD virtualisation type¶
If you are deploying Charmed PostgreSQL in a LXD model, ensure that LXD’s virtualisation type is set to virtual-machine for the Juju application.
This is because LXD does not allow /sys/kernel/tracing to be mounted in a system container (even in privileged mode) due to security isolation concerns.
To ensure that a virtual machine is used instead of a system container, you would need to add constraints, for example:
juju deploy postgresql --channel 14/stable --constraints="virt-type=virtual-machine"`.
Base (Ubuntu version)¶
If your base is ubuntu@22.04, ensure that your are using the generic flavour of Linux.
You can confirm this with
uname -r
If you do not have the generic flavour, you can enable it on a unit to be profiled as follows:
juju ssh postgresql/0 bash
sudo apt-get update && sudo apt-get install linux-image-virtual
sudo apt-get autopurge linux-image-kvm
If your application is deployed in an LXD model, run the following command:
rm /etc/default/grub.d/40-force-partuuid.cfg
Open the /etc/default/grub file with your editor of choice and replace the line that starts with GRUB_DEFAULT= with:
release=$(linux-version list | grep -e '-generic$' | sort -V | tail -n1)
GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux $release"
Exit out of the /etc/default/grub file, update GRUB, and reboot:
sudo update-grub
sudo reboot
Nothing needs to be done if the base is ubuntu@24.04, which already loads the kernel symbol table for debugging by default.
Set up the Parca backend¶
There are two potential backends:
Charmed Parca K8s (requires COS and cross-model integrations)
Polar Signals Cloud (COS is optional)
Charmed Parca K8s¶
This section goes through the steps for enabling profiling with Charmed Parca K8s as the backend.
1. Deploy cos-lite and parca-k8s¶
Refer to Getting started on MicroK8s and deploy the cos-lite bundle from the latest/edge track in a Kubernetes environment.
Then, refer to Deploy Charmed Parca on top of COS-lite to deploy Charmed Parca K8s in the same model as the cos-lite bundle.
2. Offer interfaces¶
Offer interfaces for cross-model integrations:
juju offer <parca_k8s_application_name>:parca-store-endpoint
3. Deploy and integrate parca-agent with postgresql¶
Switch to the model containing the Charmed PostgreSQL deployment, deploy Charmed Parca Agent, and integrate it with Charmed PostgreSQL:
juju switch <machine_controller_name>:<postgresql_model_name>
juju deploy parca-agent --channel latest/edge
juju integrate postgresql parca-agent
4. Integrate parca-agent with parca-k8s¶
Consume the Parca offer from Step 2 and integrate with them:
juju find-offers <k8s_controller_name>:
Tip
Do not miss the colon “:” in the command above.
Below is a sample output where k8s is the K8s controller name and cos is the model where cos-lite and parca-k8s are deployed:
Store URL Access Interfaces
k8s admin/cos.parca admin parca_store:parca-store-endpoint
Next, consume this offer so that is reachable from the current machine model:
juju consume k8s:admin/cos.parca
Finally, relate Charmed Parca Agent with the consumed offer endpoint:
juju integrate parca-agent parca
Polar Signals Cloud¶
This section goes through the steps for enabling profiling with Polar Signals Cloud (PSC) as the backend.
Note
With PSC, cos-lite and parca-k8s are not required.
This section goes through the recommended setup, where polar-signals-cloud-integrator is deployed in the same model as postgresql, and parca-agent is used to relay traffic to PSC.
If you would like to use parca-k8s to relay traffic to PSC instead, refer to Steps 1 and 2 in the Charmed Parca K8s section.
1. Deploy and integrate parca-agent with postgresql¶
In the machine model where PostgreSQL is deployed, deploy parca-agent and integrate it with postgresql:
juju deploy parca-agent --channel latest/edge
juju integrate postgresql parca-agent
2. Integrate parca-agent with polar-signals-cloud-integrator¶
Follow the guide How to integrate with Polar Signals Cloud.
View profiles¶
After the backend setup is complete, the profiles for the machines where the PostgreSQL units are running will be accessible from the Parca web interface.
If you are running Charmed Parca K8s, you can also access the link for Parca’s web interface from COS catalogue (juju run traefik/0 show-proxied-endpoints in the K8s model where cos-lite is deployed).
Furthermore, if you have cos-lite deployed, you can use Grafana to explore profiles under the Explore section with parca-k8s as the data source.
