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47e45a3cf3
DNS resolution is a critical part of `connlib`. If it is slow for whatever reason, users will notice this. To make sure we notice as well, we add `telemetry` spans to the client's and gateway's DNS resolution. For the client, this applies to all DNS queries that we forward to the upstream servers. For the gateway, this applies to all DNS resources. In addition to those IO operations, we also instrument the `match_resource_linear` function. This function operates in `O(n)` of all defined DNS resources. It _should_ be fast enough to not create an impact but it can't hurt to measure this regardless. Lastly, we also instrument `refresh_translations` on the gateway. Refreshing the DNS resolution of a DNS resource should really only happen, when the previous IP addresses become stale yet the user is still trying to send traffic to them. We don't actually have any data on how often that happens. By instrumenting it, we can gather some of this data. To make sure that none of these telemetry events and spans hurt the end-user performance, we introduce macros to `firezone-logging` that sample the creation of these events and spans at a rate of 1%. I ran a flamegraph and none of these even showed up. The most critical one here is probably the `match_resource_linear` span because it happens on every DNS query. Resolves: #7198. --------- Signed-off-by: Thomas Eizinger <thomas@eizinger.io>
headless-client
This crate acts as the CLI / headless Client, and the privileged tunnel service for the GUI Client, for both Linux and Windows.
It is built as:
headless-clientto act as the Linux / Windows headless Clientfirezone-headless-clientto act as the Linux tunnel service, Windows headless Client, or Windows tunnel service
In general, the brand name should be part of the file name, but the OS name should not be.
Running
To run the headless Client:
- Generate a new Service account token from the "Actors -> Service Accounts" section of the admin portal and save it in your secrets manager. The Firezone Linux client requires a service account at this time.
- Ensure
/etc/dev.firezone.client/tokenis only readable by root (i.e.chmod 400) - Ensure
/etc/dev.firezone.client/tokencontains the Service account token. The Client needs this before it can start - Set
FIREZONE_IDto a unique string to identify this client in the portal, e.g.export FIREZONE_ID=$(uuidgen). The client requires this variable at startup. - Set
LOG_DIRto a suitable directory for writing logsexport LOG_DIR=/tmp/firezone-logs mkdir $LOG_DIR - Now, you can start the client with:
./firezone-headless-client standalone
If you're running as an unprivileged user, you'll need the CAP_NET_ADMIN
capability to open /dev/net/tun. You can add this to the client binary with:
sudo setcap 'cap_net_admin+eip' /path/to/firezone-headless-client
Building
Assuming you have Rust installed, you can build the headless Client with:
cargo build --release -p firezone-headless-client
The binary will be in target/release/firezone-headless-client
The release on Github are built with musl. To build this way, use:
rustup target add x86_64-unknown-linux-musl
sudo apt-get install musl-tools
cargo build --release -p headless-client --target x86_64-unknown-linux-musl
Files
/etc/dev.firezone.client/token- The service account token, provided by the human administrator. Must be owned by root and have 600 permissions (r/w by owner, nobody else can read) If present, the tunnel will ignore any GUI Client and run as a headless Client. If absent, the tunnel will wait for commands from a GUI Client/usr/bin/firezone-headless-client- The tunnel binary. This must run as root so it can modify the system's DNS settings. If DNS is not needed, it only needs CAP_NET_ADMIN./usr/lib/systemd/system/firezone-headless-client.service- A systemd service unit, installed by the deb package./var/lib/dev.firezone.client/config/firezone-id- The device ID, unique across an organization. The tunnel will generate this if it's not present.