yorickdowne

Medalla non-finality mid October

What is happening with the Medalla eth2 testnet currently, Oct 17th 2020? Here's an ELI5. (Not exactly 5. Maybe 10. You get the idea.)

1. A bunch of validators turned off (maybe zinken, maybe bored, who knows)
2. We entered non-finality. This means we don't have enough validators online to agree to what the state of the network is. We need 2/3rds.
3. Some sync bugs reared their heads, in Prysm and Nimbus. We lost more validators to the bugs, not everyone has updated since
4. Non-finality increases memory and CPU requirements, we likely lost more validators because their nodes couldn't handle it
5. Either people come back in and we regain finality or
6. They don't and offline validators lose eth faster and faster, until we regain finality. Some may be ejected if their balance falls too low.

yorickdowne

Keybase proof

I hereby claim:

• I am yorickdowne on github.
• I am yorickdowne (https://keybase.io/yorickdowne) on keybase.
• I have a public key ASAMH3gm5u914DMwcR4DXVgPeCKqlPdP9Tdurg-LiKUzVQo

To claim this, I am signing this object:

yorickdowne

Use ufw for some, but not all, Docker traffic

This is a slight tweak to https://github.com/chaifeng/ufw-docker by way of https://p1ngouin.com/posts/how-to-manage-iptables-rules-with-ufw-and-docker

For an automated way of handling ufw rules via docker-compose, see https://github.com/shinebayar-g/ufw-docker-automated

Use case

I wanted Docker to keep managing its own iptables rules, including automatically opening port forwards, with the option of stepping in and restricting a port that I did not want open to "world". Container-to-container traffic should flow unimpeded,

yorickdowne

These instructions have moved.

yorickdowne

Overview

Geth 1.10.23 fixes a bug in 1.10.22, which would have resulted in missing state in its database. The Go-Ethereum team recommends to roll the chain back and let Geth catch up again, if and only if you had updated to 1.10.22. If you did not, just update to 1.10.23 now and call it done.

This is how to roll back to a previous block when using eth-docker.

Update Geth to 1.10.23

./ethd update and ./ethd up should do it.

yorickdowne

Overview

Geth, and other execution clients such as Erigon, Nethermind, and Besu, take some time on shutdown to cleanly close their database. When not given that time, they will need to resync upon restart, often for hours. This gist describes the systemd service file parameter to give them up to 5 minutes of time for a clean shutdown.

Steps

• Find your service file. It may be called /etc/systemd/system/geth.service or /etc/systemd/system/eth1.service.
• Edit it using sudo nano FILENAME, and add TimeoutStopSec=300 to the [Service] section. Here is an example of a service file after the change:

yorickdowne

Eh?

So a FOSS project might have signed releases with a GPG sig. How do you verify it on a Linux machine?

Example sigp/lighthouse, but same idea for any project.

Install gpg: sudo apt install gpg

Grab their PGP key ID from their download page and gpg --keyserver pgp.mit.edu --recv THEIRKEYID and wait

yorickdowne

Overview

Running on netcup is not much different from running on any other Linux host. The main difference is that the host is directly exposed to the Internet. Netcup provision Debian, which works well with RocketPool.

Create a non-root user

Log in via ssh: ssh root@IP. Create a non-root user: adduser USERNAME followed by usermod -aG sudo USERNAME. Log in as that user.

Set up SSH key authentication

yorickdowne

Overview

I was looking after a Dell PowerEdge R420 server with a hardware RAID card in it, a PERC8 H710P Mini. Connected to this were two WD Blue 3D NAND SATA SSDs in RAID-1, that were handling a write-intensive database: Geth, in this case.

After 11 months of running without problems, I had reason to "resync" Geth, and the server could not keep up with the required IOPS. Symptoms were Database compacting, degraded performance messages for hours, without recovery, and read/write latency in excess of 20/70ms, as measured by sudo iostat -mdx and its r_await and w_await data.

The cause of this was that the RAID controller does not support TRIM on the SSD, and the SSD's performance degraded over time because of it.

yorickdowne

Overview

Besu, an Ethereum execution layer client, is optimized for minimal database growth (7-8 GiB/week) with default parameter --bonsai-limit-trie-logs-enabled. It can use RAM for more block processing speed.

If you have 64 GiB of RAM or more, you can add --Xplugin-rocksdb-high-spec-enabled=true for better performance.

A long-running Besu DB, started before trie-log limit was enabled, will have sizeable trie log storage. This can be reduced with a one-off prune using the storage trie-log prune subcommand, assuming Besu 24.7.0 or later.

Somer Esat adjustment