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https://github.com/greenbankobservatory/barnum
Easy management of circus instances across multiple users and hosts
https://github.com/greenbankobservatory/barnum
circus
Last synced: about 13 hours ago
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Easy management of circus instances across multiple users and hosts
- Host: GitHub
- URL: https://github.com/greenbankobservatory/barnum
- Owner: GreenBankObservatory
- License: mit
- Created: 2020-02-10T20:21:19.000Z (almost 5 years ago)
- Default Branch: master
- Last Pushed: 2024-02-09T17:29:03.000Z (9 months ago)
- Last Synced: 2024-04-16T03:38:40.547Z (7 months ago)
- Topics: circus
- Language: Python
- Homepage:
- Size: 53.7 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Barnum
Easily manage multiple Circus instances across multiple hosts.
## Configuration
### Structure
Barnum currently relies on a very specific directory structure in order to discover Circus hosts:
```
tree /users/user1/circus
├── host1
│ ├── circus.ini
│ ├── circus.log
│ ├── watcher1.stderr.log
│ └── watcher1.stdout.log
└── init_circus -> /users/$USER/circus/init_circus
```
In other words, it expects that every user that is running a Circus instance will have a `~/circus` directory, and that this each child directory thereof will contain a `circus.ini` folder. Each `circus.ini` file it discovered will be parsed to determine its endpoint, and the host will be derived from the name its parent. Then, `ssh` commands will be built from this information, and used to delegate commands across multiple users/hosts simultaneously (threaded).
### Config File
You will also need a config file, so that `barnum` knows what to search for.
Create `circus_users.yaml` in the same directory as `barnum.py`. Its contents should look something like this:
```yaml
---
- user1
- user2
```
## Operations
### `barnum`
Perform Circus operations across multiple hosts
#### System Overview
```
$ python barnum.py --verbose
barnum: Circus is configured on the following hosts: host1, host2
barnum: Processing host1
barnum: Processing host2
barnum: bailey cmd: ssh -q host1 bailey --verbose
barnum: bailey cmd: ssh -q host2 bailey --verbose
bailey: Derived circus user user1 from /etc/systemd/system/circus_user1_host2.service
bailey: circus cmd: circusctl --endpoint tcp://host2:8385 status
bailey: Derived circus user user2 from /etc/systemd/system/circus_user2_host1.service
bailey: circus cmd: circusctl --endpoint tcp://host1:5775 status
bailey: Derived circus user user3 from /etc/systemd/system/circus_user3_host2.service
bailey: circus cmd: circusctl --endpoint tcp://host2:5555 status
--- HOST1 ---
--------------------------------------------------------------------------------
circus_user2_host1.service enabled active (running)
watcher1: active
================================================================================
--- HOST2 ---
--------------------------------------------------------------------------------
circus_user1_host2.service enabled active (running)
watcher2: active
--------------------------------------------------------------------------------
circus_user3_host2.service enabled active (running)
watcher3: active
--------------------------------------------------------------------------------
circus_user4_host2.service disabled inactive (dead)
No circus expected
================================================================================
```
What's happening here:
1. For each user in `circus_users.yaml`, derive the hosts it has `circus` instances on from the directory structure described above
1. For every host:
1. SSH to `host_n`
1. Use `sysctl list-unit-files` to determine all `circus` unit files
1. Examine each unit file to determine the user it is for
1. Call `bailey` for each user on `host_n`
#### Manage All Circus Instances on Given Host
Get status of all Circus instances run on `host1`:
```
$ python barnum.py host1 --verbose
Circus is configured on the following hosts: host1
Processing user1@host1
bailey cmd: ssh -q host1 /path/to/bailey user1 --verbose
circus cmd: circusctl --endpoint tcp://host1:5775 status
---
watcher1: active
```
What's happening here:
1. SSH to `host1`
1. Use `sysctl list-unit-files` to determine all `circus` unit files
1. Examine each unit file to determine the user it is for
1. For each user:
1. Construct path to `circus` config file based on given user and host
1. Parse config file to determine `circus` endpoint
1. Call `bailey` for derived endpoint
#### Manage Specific Circus Instance on Given Host
Get status of Circus instance run by `user1@host1`.
```
$ python barnum.py user1@host1 --verbose
Circus is configured on the following hosts: host1
Processing user1@host1
bailey cmd: ssh -q host1 bailey user1 --verbose
circus cmd: circusctl --endpoint tcp://host1:5775 status
---
watcher1: active
```
What's happening here:
1. SSH to `host1`
1. Construct path to `circus` config file based on given user and host
1. Parse config file to determine `circus` endpoint
1. Call `bailey` for derived endpoint
#### Sending Commands to Bailey/Circus
There are two advanced use cases here:
1. Send commands to `bailey`
2. Send commands to `circus`
3. Send commands to both `bailey` and `circus`
It is useful to experiment with these using `--dry-run`, in order to prevent things from getting broken. For example,
```
$ python barnum.py user1@host1 --verbose --dry-run
barnum: Processing user1@host1
---
DRY RUN; would execute: ssh -q host1 bailey user1 --verbose
```
##### Send commands to `bailey`
This would print the help message for every `bailey` instance:
```$ python barnum.py -- --help```
To send specific `circus` commands to each `bailey` instance, you'll need to use something like the following:
```$ python barnum.py user1@host1 --verbose -- -- stats```
Everything following the `--` will be sent directly to `bailey`, without any changes. `bailey` will then send everything after the _second_ `--` directly to `circus` (more on that below).
### `bailey`
Perform Circus operations on a single hosts (but possibly multiple users)
#### Manage All Circus Instances on Current Host
Get status of all Circus instances run on current host (`host1`):
```
$ bailey --verbose
--- host1 ---
--------------------------------------------------------------------------------
circus_user1_host1.service disabled inactive (dead)
No circus expected
--------------------------------------------------------------------------------
bailey: Derived circus user user1 from /etc/systemd/system/circus_user1_host1.service
bailey: circus cmd: circusctl --endpoint tcp://host1:5755 status
circus_user1_host1.service enabled active (running)
watcher1: active
================================================================================
```
What's happening here:
1. Use `sysctl list-unit-files` to determine all `circus` unit files
1. Examine each unit file to determine the user it is for
1. For each user:
1. Construct path to `circus` config file based on given user and host
1. Parse config file to determine `circus` endpoint
1. Call `bailey` for derived endpoint
#### Manage Specific Circus Instance on Current Host
Get status of Circus instance run by `user1@host1` (given user at current host).
```
$ bailey user1 --verbose
bailey: circus cmd: circusctl --endpoint tcp://host1:5555 status
watcher1: active
```
What's happening here:
1. Construct path to `circus` config file based on given user and host
1. Parse config file to determine `circus` endpoint
1. Call `bailey` for derived endpoint
##### Send commands to `circus`
To send specific `circus` commands, you'll need to use something like the following:
```$ python barnum.py user1@host1 --verbose -- stats```
Everything following the `--` will be sent directly to `circus`, without any changes