MyFavMirrors
/
headscale
mirror of https://github.com/juanfont/headscale.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix/improve documentation formatting (#1575) 

* Fix docs formatting

* .prettierignore add docu

---------

Co-authored-by: ohdearaugustin <ohdearaugustin@users.noreply.github.com>
This commit is contained in:
Maja Bojarska 2024-03-22 19:55:20 +01:00 committed by GitHub
parent 74ff14eb30
commit 4d9021047f
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
6 changed files with 341 additions and 337 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
.prettierignore
View File

@ -1 +1,6 @@
.github/workflows/test-integration-v2* .github/workflows/test-integration-v2*
docs/dns-records.md
docs/running-headscale-container.md
docs/running-headscale-linux-manual.md
docs/running-headscale-linux.md
docs/running-headscale-openbsd.md

12
docs/dns-records.md
View File

@ -18,8 +18,8 @@ An example use case is to serve apps on the same host via a reverse proxy like N
1. Change the `config.yaml` to contain the desired records like so: 1. Change the `config.yaml` to contain the desired records like so:
```yaml ```yaml
dns_config: dns_config:
... ...
extra_records: extra_records:
- name: "prometheus.myvpn.example.com" - name: "prometheus.myvpn.example.com"
@ -30,11 +30,13 @@ dns_config:
type: "A" type: "A"
value: "100.64.0.3" value: "100.64.0.3"
... ...
``` ```
2. Restart your headscale instance. 1. Restart your headscale instance.
Beware of the limitations listed later on! !!! warning
Beware of the limitations listed later on!
### 2. Verify that the records are set ### 2. Verify that the records are set

143
docs/running-headscale-container.md
View File

@ -17,66 +17,66 @@ not work with alternatives like [Podman](https://podman.io). The Docker image ca
1. Prepare a directory on the host Docker node in your directory of choice, used to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database: 1. Prepare a directory on the host Docker node in your directory of choice, used to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database:
```shell ```shell
mkdir -p ./headscale/config mkdir -p ./headscale/config
cd ./headscale cd ./headscale
``` ```
2. Create an empty SQlite datebase in the headscale directory: 1. Create an empty SQlite datebase in the headscale directory:
```shell ```shell
touch ./config/db.sqlite touch ./config/db.sqlite
``` ```
3. **(Strongly Recommended)** Download a copy of the [example configuration](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository. 1. **(Strongly Recommended)** Download a copy of the [example configuration](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository.
Using wget: - Using `wget`:
```shell ```shell
wget -O ./config/config.yaml https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml wget -O ./config/config.yaml https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml
``` ```
Using curl: - Using `curl`:
```shell ```shell
curl https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml -o ./config/config.yaml curl https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml -o ./config/config.yaml
``` ```
**(Advanced)** If you would like to hand craft a config file **instead** of downloading the example config file, create a blank `headscale` configuration in the headscale directory to edit: - **(Advanced)** If you would like to hand craft a config file **instead** of downloading the example config file, create a blank `headscale` configuration in the headscale directory to edit:
```shell ```shell
touch ./config/config.yaml touch ./config/config.yaml
``` ```
Modify the config file to your preferences before launching Docker container. Modify the config file to your preferences before launching Docker container.
Here are some settings that you likely want: Here are some settings that you likely want:
```yaml ```yaml
# Change to your hostname or host IP # Change to your hostname or host IP
server_url: http://your-host-name:8080 server_url: http://your-host-name:8080
# Listen to 0.0.0.0 so it's accessible outside the container # Listen to 0.0.0.0 so it's accessible outside the container
metrics_listen_addr: 0.0.0.0:9090 metrics_listen_addr: 0.0.0.0:9090
# The default /var/lib/headscale path is not writable in the container # The default /var/lib/headscale path is not writable in the container
noise: noise:
private_key_path: /etc/headscale/noise_private.key private_key_path: /etc/headscale/noise_private.key
# The default /var/lib/headscale path is not writable in the container # The default /var/lib/headscale path is not writable in the container
derp: derp:
private_key_path: /etc/headscale/private.key private_key_path: /etc/headscale/private.key
# The default /var/run/headscale path is not writable in the container # The default /var/run/headscale path is not writable in the container
unix_socket: /etc/headscale/headscale.sock unix_socket: /etc/headscale/headscale.sock
# The default /var/lib/headscale path is not writable in the container # The default /var/lib/headscale path is not writable in the container
database.type: sqlite3 database.type: sqlite3
database.sqlite.path: /etc/headscale/db.sqlite database.sqlite.path: /etc/headscale/db.sqlite
``` ```
Alternatively, you can mount `/var/lib` and `/var/run` from your host system by adding Alternatively, you can mount `/var/lib` and `/var/run` from your host system by adding
`--volume $(pwd)/lib:/var/lib/headscale` and `--volume $(pwd)/run:/var/run/headscale` `--volume $(pwd)/lib:/var/lib/headscale` and `--volume $(pwd)/run:/var/run/headscale`
in the next step. in the next step.
4. Start the headscale server while working in the host headscale directory: 1. Start the headscale server while working in the host headscale directory:
```shell ```shell
docker run \ docker run \
--name headscale \ --name headscale \
--detach \ --detach \
--volume $(pwd)/config:/etc/headscale/ \ --volume $(pwd)/config:/etc/headscale/ \
@ -84,20 +84,19 @@ docker run \
--publish 127.0.0.1:9090:9090 \ --publish 127.0.0.1:9090:9090 \
headscale/headscale:<VERSION> \ headscale/headscale:<VERSION> \
headscale serve headscale serve
```
``` Note: use `0.0.0.0:8080:8080` instead of `127.0.0.1:8080:8080` if you want to expose the container externally.
Note: use `0.0.0.0:8080:8080` instead of `127.0.0.1:8080:8080` if you want to expose the container externally. This command will mount `config/` under `/etc/headscale`, forward port 8080 out of the container so the
`headscale` instance becomes available and then detach so headscale runs in the background.
This command will mount `config/` under `/etc/headscale`, forward port 8080 out of the container so the Example `docker-compose.yaml`
`headscale` instance becomes available and then detach so headscale runs in the background.
Example `docker-compose.yaml` ```yaml
version: "3.7"
```yaml services:
version: "3.7"
services:
headscale: headscale:
image: headscale/headscale:0.22.3 image: headscale/headscale:0.22.3
restart: unless-stopped restart: unless-stopped
@ -109,35 +108,33 @@ services:
# pls change [config_path] to the fullpath of the config folder just created # pls change [config_path] to the fullpath of the config folder just created
- [config_path]:/etc/headscale - [config_path]:/etc/headscale
command: headscale serve command: headscale serve
```
``` 1. Verify `headscale` is running:
Follow the container logs:
5. Verify `headscale` is running: ```shell
docker logs --follow headscale
```
Follow the container logs: Verify running containers:
```shell ```shell
docker logs --follow headscale docker ps
``` ```
Verify running containers: Verify `headscale` is available:
```shell ```shell
docker ps curl http://127.0.0.1:9090/metrics
``` ```
Verify `headscale` is available: 1. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)):
```shell ```shell
curl http://127.0.0.1:9090/metrics docker exec headscale \
```
6. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)):
```shell
docker exec headscale \
headscale users create myfirstuser headscale users create myfirstuser
``` ```
### Register a machine (normal login) ### Register a machine (normal login)

193
docs/running-headscale-linux-manual.md
View File

@ -15,78 +15,77 @@ describing how to make `headscale` run properly in a server environment.
1. Download the latest [`headscale` binary from GitHub's release page](https://github.com/juanfont/headscale/releases): 1. Download the latest [`headscale` binary from GitHub's release page](https://github.com/juanfont/headscale/releases):
```shell ```shell
wget --output-document=/usr/local/bin/headscale \ wget --output-document=/usr/local/bin/headscale \
https://github.com/juanfont/headscale/releases/download/v<HEADSCALE VERSION>/headscale_<HEADSCALE VERSION>_linux_<ARCH> https://github.com/juanfont/headscale/releases/download/v<HEADSCALE VERSION>/headscale_<HEADSCALE VERSION>_linux_<ARCH>
``` ```
2. Make `headscale` executable: 1. Make `headscale` executable:
```shell ```shell
chmod +x /usr/local/bin/headscale chmod +x /usr/local/bin/headscale
``` ```
3. Prepare a directory to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database: 1. Prepare a directory to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database:
```shell ```shell
# Directory for configuration # Directory for configuration
mkdir -p /etc/headscale mkdir -p /etc/headscale
# Directory for Database, and other variable data (like certificates) # Directory for Database, and other variable data (like certificates)
mkdir -p /var/lib/headscale mkdir -p /var/lib/headscale
# or if you create a headscale user: # or if you create a headscale user:
useradd \ useradd \
--create-home \ --create-home \
--home-dir /var/lib/headscale/ \ --home-dir /var/lib/headscale/ \
--system \ --system \
--user-group \ --user-group \
--shell /usr/sbin/nologin \ --shell /usr/sbin/nologin \
headscale headscale
``` ```
4. Create an empty SQLite database: 1. Create an empty SQLite database:
```shell ```shell
touch /var/lib/headscale/db.sqlite touch /var/lib/headscale/db.sqlite
``` ```
5. Create a `headscale` configuration: 1. Create a `headscale` configuration:
```shell ```shell
touch /etc/headscale/config.yaml touch /etc/headscale/config.yaml
``` ```
**(Strongly Recommended)** Download a copy of the [example configuration][config-example.yaml](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository. **(Strongly Recommended)** Download a copy of the [example configuration][config-example.yaml](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository.
6. Start the headscale server: 1. Start the headscale server:
```shell ```shell
headscale serve headscale serve
``` ```
This command will start `headscale` in the current terminal session. This command will start `headscale` in the current terminal session.
--- ---
To continue the tutorial, open a new terminal and let it run in the background. To continue the tutorial, open a new terminal and let it run in the background.
Alternatively use terminal emulators like [tmux](https://github.com/tmux/tmux) or [screen](https://www.gnu.org/software/screen/). Alternatively use terminal emulators like [tmux](https://github.com/tmux/tmux) or [screen](https://www.gnu.org/software/screen/).
To run `headscale` in the background, please follow the steps in the [SystemD section](#running-headscale-in-the-background-with-systemd) before continuing. To run `headscale` in the background, please follow the steps in the [SystemD section](#running-headscale-in-the-background-with-systemd) before continuing.
7. Verify `headscale` is running: 1. Verify `headscale` is running:
Verify `headscale` is available:
Verify `headscale` is available: ```shell
curl http://127.0.0.1:9090/metrics
```
```shell 1. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)):
curl http://127.0.0.1:9090/metrics
```
8. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)): ```shell
headscale users create myfirstuser
```shell ```
headscale users create myfirstuser
```
### Register a machine (normal login) ### Register a machine (normal login)
@ -118,81 +117,81 @@ tailscale up --login-server <YOUR_HEADSCALE_URL> --authkey <YOUR_AUTH_KEY>
## Running `headscale` in the background with SystemD ## Running `headscale` in the background with SystemD
:warning: **Deprecated**: This part is very outdated and you should use the [pre-packaged Headscale for this](./running-headscale-linux.md :warning: **Deprecated**: This part is very outdated and you should use the [pre-packaged Headscale for this](./running-headscale-linux.md)
This section demonstrates how to run `headscale` as a service in the background with [SystemD](https://www.freedesktop.org/wiki/Software/systemd/). This section demonstrates how to run `headscale` as a service in the background with [SystemD](https://www.freedesktop.org/wiki/Software/systemd/).
This should work on most modern Linux distributions. This should work on most modern Linux distributions.
1. Create a SystemD service configuration at `/etc/systemd/system/headscale.service` containing: 1. Create a SystemD service configuration at `/etc/systemd/system/headscale.service` containing:
```systemd ```systemd
[Unit] [Unit]
Description=headscale controller Description=headscale controller
After=syslog.target After=syslog.target
After=network.target After=network.target
[Service] [Service]
Type=simple Type=simple
User=headscale User=headscale
Group=headscale Group=headscale
ExecStart=/usr/local/bin/headscale serve ExecStart=/usr/local/bin/headscale serve
Restart=always Restart=always
RestartSec=5 RestartSec=5
# Optional security enhancements # Optional security enhancements
NoNewPrivileges=yes NoNewPrivileges=yes
PrivateTmp=yes PrivateTmp=yes
ProtectSystem=strict ProtectSystem=strict
ProtectHome=yes ProtectHome=yes
WorkingDirectory=/var/lib/headscale WorkingDirectory=/var/lib/headscale
ReadWritePaths=/var/lib/headscale /var/run/headscale ReadWritePaths=/var/lib/headscale /var/run/headscale
AmbientCapabilities=CAP_NET_BIND_SERVICE AmbientCapabilities=CAP_NET_BIND_SERVICE
RuntimeDirectory=headscale RuntimeDirectory=headscale
[Install] [Install]
WantedBy=multi-user.target WantedBy=multi-user.target
``` ```
Note that when running as the headscale user ensure that, either you add your current user to the headscale group: Note that when running as the headscale user ensure that, either you add your current user to the headscale group:
```shell ```shell
usermod -a -G headscale current_user usermod -a -G headscale current_user
``` ```
or run all headscale commands as the headscale user: or run all headscale commands as the headscale user:
```shell ```shell
su - headscale su - headscale
``` ```
2. In `/etc/headscale/config.yaml`, override the default `headscale` unix socket with path that is writable by the `headscale` user or group: 1. In `/etc/headscale/config.yaml`, override the default `headscale` unix socket with path that is writable by the `headscale` user or group:
```yaml ```yaml
unix_socket: /var/run/headscale/headscale.sock unix_socket: /var/run/headscale/headscale.sock
``` ```
3. Reload SystemD to load the new configuration file: 1. Reload SystemD to load the new configuration file:
```shell ```shell
systemctl daemon-reload systemctl daemon-reload
``` ```
4. Enable and start the new `headscale` service: 1. Enable and start the new `headscale` service:
```shell ```shell
systemctl enable --now headscale systemctl enable --now headscale
``` ```
5. Verify the headscale service: 1. Verify the headscale service:
```shell ```shell
systemctl status headscale systemctl status headscale
``` ```
Verify `headscale` is available: Verify `headscale` is available:
```shell ```shell
curl http://127.0.0.1:9090/metrics curl http://127.0.0.1:9090/metrics
``` ```
`headscale` will now run in the background and start at boot. `headscale` will now run in the background and start at boot.

46
docs/running-headscale-linux.md
View File

@ -22,40 +22,40 @@ configuration (`/etc/headscale/config.yaml`).
1. Download the lastest Headscale package for your platform (`.deb` for Ubuntu and Debian) from [Headscale's releases page](https://github.com/juanfont/headscale/releases): 1. Download the lastest Headscale package for your platform (`.deb` for Ubuntu and Debian) from [Headscale's releases page](https://github.com/juanfont/headscale/releases):
```shell ```shell
wget --output-document=headscale.deb \ wget --output-document=headscale.deb \
https://github.com/juanfont/headscale/releases/download/v<HEADSCALE VERSION>/headscale_<HEADSCALE VERSION>_linux_<ARCH>.deb https://github.com/juanfont/headscale/releases/download/v<HEADSCALE VERSION>/headscale_<HEADSCALE VERSION>_linux_<ARCH>.deb
``` ```
2. Install Headscale: 1. Install Headscale:
```shell ```shell
sudo dpkg --install headscale.deb sudo dpkg --install headscale.deb
``` ```
3. Enable Headscale service, this will start Headscale at boot: 1. Enable Headscale service, this will start Headscale at boot:
```shell ```shell
sudo systemctl enable headscale sudo systemctl enable headscale
``` ```
4. Configure Headscale by editing the configuration file: 1. Configure Headscale by editing the configuration file:
```shell ```shell
nano /etc/headscale/config.yaml nano /etc/headscale/config.yaml
``` ```
5. Start Headscale: 1. Start Headscale:
```shell ```shell
sudo systemctl start headscale sudo systemctl start headscale
``` ```
6. Check that Headscale is running as intended: 1. Check that Headscale is running as intended:
```shell ```shell
systemctl status headscale systemctl status headscale
``` ```
## Using Headscale ## Using Headscale

201
docs/running-headscale-openbsd.md
View File

@ -15,115 +15,116 @@ describing how to make `headscale` run properly in a server environment.
## Install `headscale` ## Install `headscale`
1. Install from ports (Not Recommend) 1. Install from ports (not recommended)
As of OpenBSD 7.2, there's a headscale in ports collection, however, it's severely outdated(v0.12.4). !!! info
You can install it via `pkg_add headscale`.
2. Install from source on OpenBSD 7.2 As of OpenBSD 7.2, there's a headscale in ports collection, however, it's severely outdated(v0.12.4). You can install it via `pkg_add headscale`.
```shell 1. Install from source on OpenBSD 7.2
# Install prerequistes
pkg_add go
git clone https://github.com/juanfont/headscale.git ```shell
# Install prerequistes
pkg_add go
cd headscale git clone https://github.com/juanfont/headscale.git
# optionally checkout a release cd headscale
# option a. you can find offical relase at https://github.com/juanfont/headscale/releases/latest
# option b. get latest tag, this may be a beta release
latestTag=$(git describe --tags `git rev-list --tags --max-count=1`)
git checkout $latestTag # optionally checkout a release
# option a. you can find offical relase at https://github.com/juanfont/headscale/releases/latest
# option b. get latest tag, this may be a beta release
latestTag=$(git describe --tags `git rev-list --tags --max-count=1`)
go build -ldflags="-s -w -X github.com/juanfont/headscale/cmd/headscale/cli.Version=$latestTag" github.com/juanfont/headscale git checkout $latestTag
# make it executable go build -ldflags="-s -w -X github.com/juanfont/headscale/cmd/headscale/cli.Version=$latestTag" github.com/juanfont/headscale
chmod a+x headscale
# copy it to /usr/local/sbin # make it executable
cp headscale /usr/local/sbin chmod a+x headscale
```
3. Install from source via cross compile # copy it to /usr/local/sbin
cp headscale /usr/local/sbin
```
```shell 1. Install from source via cross compile
# Install prerequistes
# 1. go v1.20+: headscale newer than 0.21 needs go 1.20+ to compile
# 2. gmake: Makefile in the headscale repo is written in GNU make syntax
git clone https://github.com/juanfont/headscale.git ```shell
# Install prerequistes
# 1. go v1.20+: headscale newer than 0.21 needs go 1.20+ to compile
# 2. gmake: Makefile in the headscale repo is written in GNU make syntax
cd headscale git clone https://github.com/juanfont/headscale.git
# optionally checkout a release cd headscale
# option a. you can find offical relase at https://github.com/juanfont/headscale/releases/latest
# option b. get latest tag, this may be a beta release
latestTag=$(git describe --tags `git rev-list --tags --max-count=1`)
git checkout $latestTag # optionally checkout a release
# option a. you can find offical relase at https://github.com/juanfont/headscale/releases/latest
# option b. get latest tag, this may be a beta release
latestTag=$(git describe --tags `git rev-list --tags --max-count=1`)
make build GOOS=openbsd git checkout $latestTag
# copy headscale to openbsd machine and put it in /usr/local/sbin make build GOOS=openbsd
```
# copy headscale to openbsd machine and put it in /usr/local/sbin
```
## Configure and run `headscale` ## Configure and run `headscale`
1. Prepare a directory to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database: 1. Prepare a directory to hold `headscale` configuration and the [SQLite](https://www.sqlite.org/) database:
```shell ```shell
# Directory for configuration # Directory for configuration
mkdir -p /etc/headscale mkdir -p /etc/headscale
# Directory for Database, and other variable data (like certificates) # Directory for Database, and other variable data (like certificates)
mkdir -p /var/lib/headscale mkdir -p /var/lib/headscale
``` ```
2. Create an empty SQLite database: 1. Create an empty SQLite database:
```shell ```shell
touch /var/lib/headscale/db.sqlite touch /var/lib/headscale/db.sqlite
``` ```
3. Create a `headscale` configuration: 1. Create a `headscale` configuration:
```shell ```shell
touch /etc/headscale/config.yaml touch /etc/headscale/config.yaml
``` ```
**(Strongly Recommended)** Download a copy of the [example configuration][config-example.yaml](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository. **(Strongly Recommended)** Download a copy of the [example configuration][config-example.yaml](https://github.com/juanfont/headscale/blob/main/config-example.yaml) from the headscale repository.
4. Start the headscale server: 1. Start the headscale server:
```shell ```shell
headscale serve headscale serve
``` ```
This command will start `headscale` in the current terminal session. This command will start `headscale` in the current terminal session.
--- ***
To continue the tutorial, open a new terminal and let it run in the background. To continue the tutorial, open a new terminal and let it run in the background.
Alternatively use terminal emulators like [tmux](https://github.com/tmux/tmux). Alternatively use terminal emulators like [tmux](https://github.com/tmux/tmux).
To run `headscale` in the background, please follow the steps in the [rc.d section](#running-headscale-in-the-background-with-rcd) before continuing. To run `headscale` in the background, please follow the steps in the [rc.d section](#running-headscale-in-the-background-with-rcd) before continuing.
5. Verify `headscale` is running: 1. Verify `headscale` is running:
Verify `headscale` is available: Verify `headscale` is available:
```shell ```shell
curl http://127.0.0.1:9090/metrics curl http://127.0.0.1:9090/metrics
``` ```
6. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)): 1. Create a user ([tailnet](https://tailscale.com/kb/1136/tailnet/)):
```shell ```shell
headscale users create myfirstuser headscale users create myfirstuser
``` ```
### Register a machine (normal login) ### Register a machine (normal login)
@ -159,51 +160,51 @@ This section demonstrates how to run `headscale` as a service in the background
1. Create a rc.d service at `/etc/rc.d/headscale` containing: 1. Create a rc.d service at `/etc/rc.d/headscale` containing:
```shell ```shell
#!/bin/ksh #!/bin/ksh
daemon="/usr/local/sbin/headscale" daemon="/usr/local/sbin/headscale"
daemon_logger="daemon.info" daemon_logger="daemon.info"
daemon_user="root" daemon_user="root"
daemon_flags="serve" daemon_flags="serve"
daemon_timeout=60 daemon_timeout=60
. /etc/rc.d/rc.subr . /etc/rc.d/rc.subr
rc_bg=YES rc_bg=YES
rc_reload=NO rc_reload=NO
rc_cmd $1 rc_cmd $1
``` ```
2. `/etc/rc.d/headscale` needs execute permission: 1. `/etc/rc.d/headscale` needs execute permission:
```shell ```shell
chmod a+x /etc/rc.d/headscale chmod a+x /etc/rc.d/headscale
``` ```
3. Start `headscale` service: 1. Start `headscale` service:
```shell ```shell
rcctl start headscale rcctl start headscale
``` ```
4. Make `headscale` service start at boot: 1. Make `headscale` service start at boot:
```shell ```shell
rcctl enable headscale rcctl enable headscale
``` ```
5. Verify the headscale service: 1. Verify the headscale service:
```shell ```shell
rcctl check headscale rcctl check headscale
``` ```
Verify `headscale` is available: Verify `headscale` is available:
```shell ```shell
curl http://127.0.0.1:9090/metrics curl http://127.0.0.1:9090/metrics
``` ```
`headscale` will now run in the background and start at boot. `headscale` will now run in the background and start at boot.