Overview

Some chains allow the node operator to provide a custom configuration. AvalancheGo can read chain configurations from files and pass them to the corresponding chains on initialization.

AvalancheGo looks for these files in the directory specified by --chain-config-dir AvalancheGo flag, as documented here. If omitted, value defaults to $HOME/.avalanchego/configs/chains. This directory can have sub-directories whose names are chain IDs or chain aliases. Each sub-directory contains the configuration for the chain specified in the directory name. Each sub-directory should contain a file named config, whose value is passed in when the corresponding chain is initialized (see below for extension). For example, config for the C-Chain should be at: {chain-config-dir}/C/config.json.

This also applies to Subnets, for example, if a Subnet's chain id is 2ebCneCbwthjQ1rYT41nhd7M76Hc6YmosMAQrTFhBq8qeqh6tt, the config for this chain should be at {chain-config-dir}/2ebCneCbwthjQ1rYT41nhd7M76Hc6YmosMAQrTFhBq8qeqh6tt/config.json

The filename extension that these files should have, and the contents of these files, is VM-dependent. For example, some chains may expect config.txt while others expect config.json. If multiple files are provided with the same name but different extensions (for example config.json and config.txt) in the same sub-directory, AvalancheGo will exit with an error.

For a given chain, AvalancheGo will follow the sequence below to look for its config file, where all folder and file names are case sensitive:

1. First it looks for a config sub-directory whose name is the Chain ID.
2. If it isn't found, it looks for a config sub-directory whose name is the chain's primary alias.
3. If it's not found, it looks for a config sub-directory whose name is another alias for the chain

Alternatively, for some setups it might be more convenient to provide config entirely via the command line. For that, you can use AvalancheGo --chain-config-content flag, as documented here.

It is not required to provide these custom configurations. If they are not provided, a VM-specific default config will be used. And the values of these default config are printed when the node starts.

Subnet Chain Configs

As mentioned above, if a Subnet's chain id is 2ebCneCbwthjQ1rYT41nhd7M76Hc6YmosMAQrTFhBq8qeqh6tt, the config for this chain should be at {chain-config-dir}/2ebCneCbwthjQ1rYT41nhd7M76Hc6YmosMAQrTFhBq8qeqh6tt/config.json

FAQs

• When using getBlockNumber it will return finalized blocks. To allow for queries for unfinalized (not yet accepted) blocks/transactions use allow-unfainalized-queries and set to true (by default it is set to false)
• When deactivating offline pruning (pruning-enabled: false) from previously enabled state, this will not impact blocks whose state was already pruned. This will return missing trie node errors, as the node can't lookup the state of a historical block if that state was deleted.