Add Parachain Grafana dashboards (#4578)

* Read me.

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* Add dashboards and readme

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* Update root readme

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* Add dashboard links in readme

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* updates

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* Updates

Signed-off-by: Andrei Sandu <andrei-mihail@parity.io>

* bump zombienet version

Co-authored-by: Javier Viola <javier@parity.io>

polkadot/README.md

@@ -243,6 +243,12 @@ polkadot --chain=polkadot-local --bob -d /tmp/bob --port 30334 --bootnodes '/ip4
 
 Ensure you replace `ALICE_BOOTNODE_ID_HERE` with the node ID from the output of the first terminal.
 
+### Monitoring
+
+[Setup Prometheus and Grafana](https://wiki.polkadot.network/docs/maintain-guides-how-to-monitor-your-node).
+
+Once you set this up you can take a look at the [Polkadot Grafana dashboards](grafana/README.md) that we currently maintain. 
+
 ### Using Docker
 
 [Using Docker](doc/docker.md)

polkadot/grafana/README.md

+# Do I need this ?
+
+Polkadot nodes collect and produce Prometheus metrics and logs. These include health, performance and debug 
+information such as last finalized block, height of the chain, and many other deeper implementation details 
+of the Polkadot/Substrate node subsystems. These are crucial pieces of information that one needs to successfully 
+monitor the liveliness and performance of a network and its validators.
+
+# How does it work ?
+
+Just import the dashboard JSON files from this folder in your Grafana installation. All dashboards are grouped in 
+folder percategory (like for example `parachains`). The files have been created by Grafana export functionality and
+follow the data model specified [here](https://grafana.com/docs/grafana/latest/dashboards/json-model/).
+
+We aim to keep the dashboards here in sync with the implementation, except dashboards for development and 
+testing.
+
+# Contributing
+
+**Your contributions are most welcome!** 
+
+Please make sure to follow the following design guidelines:
+- Add a new entry in this file and describe the usecase and key metrics
+- Ensure proper names and descriptions for dashboard panels and add relevant documentation when needed. 
+This is very important as not all users have similar depth of understanding of the implementation 
+- Have labels for axis
+- All values have proper units of measurement
+- A crisp and clear color scheme is used
+
+# Prerequisites
+
+Before you continue make sure you have Grafana set up, or otherwise follow this 
+[guide](https://wiki.polkadot.network/docs/maintain-guides-how-to-monitor-your-node). 
+
+You might also need to [setup Loki](https://grafana.com/go/webinar/loki-getting-started/).
+
+# Alerting
+
+Alerts are currently out of the scope of the dashboards, but their setup can be done manually or automated
+(see [installing and configuring Alert Manager](https://wiki.polkadot.network/docs/maintain-guides-how-to-monitor-your-node#installing-and-configuring-alertmanager-optional))
+
+# Dashboards
+
+This section is a list of dashboards, their use case as well as the key metrics that are covered.
+
+## Node Versions
+
+Useful for monitoring versions and logs of validator nodes. Includes time series panels that 
+track node warning and error log rates. These can be further investigated in Grafana Loki.
+
+Requires Loki for log aggregation and querying.
+
+[Dashboard JSON](general/kusama_deployment.json)
+
+## Parachain Status
+
+This dashboard allows you to see at a glance how fast are candidates approved, disputed and
+finalized. It was originally designed for observing liveliness after parachain deployment in
+ Kusama/Polkadot, but can be useful generally in production or testing.
+
+It includes panels covering key subsystems of the parachain node side implementation:
+- Backing
+- PVF execution
+- Approval voting
+- Disputes coordinator
+- Chain selection
+
+It is important to note that this dashboard applies only for validator nodes. The prometheus 
+queries assume the `instance` label value contains the string `validator` only for validator nodes. 
+
+[Dashboard JSON](parachains/status.json)
+
+### Key liveliness indicators
+- **Relay chain finality lag**. How far behind finality is compared to the current best block. By design,
+ GRANDPA never finalizes past last 2 blocks, so this value is always >=2 blocks.
+- **Approval checking finality lag**. The distance (in blocks) between the chain head and the last block 
+on which Approval voting is happening. The block is generally the highest approved ancestor of the head 
+block and the metric is computed during relay chain selection.
+- **Disputes finality lag**. How far behind the chain head is the last approved and non disputed block. 
+This value is always higher than approval checking lag as it further restricts finality to only undisputed 
+chains.
+- **PVF preparation and execution time**. Each parachain has it's own PVF (parachain validation function): 
+a wasm blob that is executed by validators during backing, approval checking and disputing. The PVF 
+preparation time refers to the time it takes for the PVF wasm to be compiled. This step is done once and 
+then result cached. PVF execution will use the resulting artifact to execute the PVF for a given candidate. 
+PVFs are expected to have a limited execution time to ensure there is enough time left for the parachain 
+block to be included in the relay block.
+- **Time to recover and check candidate**. This is part of approval voting and covers the time it takes 
+to recover the candidate block available data from other validators, check it (includes PVF execution time)
+and issue statement or initiate dispute.
+- **Assignment delay tranches**. Approval voting is designed such that validators assigned to check a specific 
+candidate are split up into equal delay tranches (0.5 seconds each). All validators checks are ordered by the delay 
+tranche index. Early tranches of validators have the opportunity to check the candidate first before later tranches 
+that act as as backups in case of no shows.