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Description:

osfaults 0.2.7

OpenStack fault-injection library
The library does destructive actions inside an OpenStack cloud. It provides
an abstraction layer over different types of cloud deployments. The actions
are implemented as drivers (e.g. DevStack driver, Fuel driver, Libvirt driver,
IPMI driver, Universal driver).

Free software: Apache license
Documentation: https://os-faults.readthedocs.io/
Source: https://opendev.org/performa/os-faults/
Bugs: https://bugs.launchpad.net/os-faults

Installation
Requirements
Ansible is required and should be installed manually system-wide or in virtual
environment. Please refer to [https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html]
for installation instructions.
Regular installation:
pip install os-faults
The library contains optional libvirt driver [https://pypi.org/project/libvirt-python/], if you plan to use it,
please use the following command to install os-faults with extra dependencies:
pip install os-faults libvirt-python

Configuration
The cloud deployment configuration is specified in JSON/YAML format or Python dictionary.

The library operates with 2 types of objects:

service - is a software that runs in the cloud, e.g. nova-api
container - is a software that runs in the cloud, e.g. neutron_api
nodes - nodes that host the cloud, e.g. a server with a hostname

Example 1. DevStack
Connection to DevStack can be specified using the following YAML file:
cloud_management:
driver: devstack
args:
address: devstack.local
auth:
username: stack
private_key_file: cloud_key
iface: enp0s8
OS-Faults library will connect to DevStack by address devstack.local with user stack
and SSH key located in file cloud_key. Default networking interface is specified with
parameter iface. Note that user should have sudo permissions (by default DevStack user has them).
DevStack driver is responsible for service discovery. For more details please refer
to driver documentation: http://os-faults.readthedocs.io/en/latest/drivers.html#devstack-systemd-devstackmanagement

Example 2. An OpenStack with services, containers and power management
An arbitrary OpenStack can be handled too with help of universal driver.
In this example os-faults is used as Python library.
cloud_config = {
'cloud_management': {
'driver': 'universal',
},
'node_discover': {
'driver': 'node_list',
'args': [
{
'ip': '192.168.5.127',
'auth': {
'username': 'root',
'private_key_file': 'openstack_key',
}
},
{
'ip': '192.168.5.128',
'auth': {
'username': 'root',
'private_key_file': 'openstack_key',
}
}
]
},
'services': {
'memcached': {
'driver': 'system_service',
'args': {
'service_name': 'memcached',
'grep': 'memcached',
}
}
},
'containers': {
'neutron_api': {
'driver': 'docker_container',
'args': {
'container_name': 'neutron_api',
}
}
},
'power_managements': [
{
'driver': 'libvirt',
'args': {
'connection_uri': 'qemu+unix:///system',
}
},
]
}
The config contains all OpenStack nodes with credentials and all
services/containers. OS-Faults will automatically figure out the mapping
between services/containers and nodes. Power management configuration is
flexible and supports mixed bare-metal / virtualized deployments.
First let’s establish a connection to the cloud and verify it:
cloud_management = os_faults.connect(cloud_config)
cloud_management.verify()
The library can also read configuration from a file in YAML or JSON format.
The configuration file can be specified in the OS_FAULTS_CONFIG environment
variable. By default the library searches for file os-faults.{json,yaml,yml}
in one of locations:

current directory
~/.config/os-faults
/etc/openstack

Now let’s make some destructive action:
cloud_management.get_service(name='memcached').kill()
cloud_management.get_container(name='neutron_api').restart()

Human API
Human API is simplified and self-descriptive. It includes multiple commands
that are written like normal English sentences.
Service-oriented command performs specified action against service on
all, on one random node or on the node specified by FQDN:
<action> <service> service [on (random|one|single|<fqdn> node[s])]

Examples:

Restart Keystone service - restarts Keystone service on all nodes.
kill nova-api service on one node - kills Nova API on one
randomly-picked node.

Container-oriented command performs specified action against container
on all, on one random node or on the node specified by FQDN:
<action> <container> container [on (random|one|single|<fqdn> node[s])]

Examples:

Restart neutron_ovs_agent container - restarts neutron_ovs_agent
container on all nodes.
Terminate neutron_api container on one node - stops Neutron API
container on one randomly-picked node.

Node-oriented command performs specified action on node specified by FQDN
or set of service’s nodes:
<action> [random|one|single|<fqdn>] node[s] [with <service> service]

Examples:

Reboot one node with mysql - reboots one random node with MySQL.
Reset node-2.domain.tld node - resets node node-2.domain.tld.

Network-oriented command is a subset of node-oriented and performs network
management operation on selected nodes:
<action> <network> network on [random|one|single|<fqdn>] node[s]
[with <service> service]

Examples:

Disconnect management network on nodes with rabbitmq service - shuts
down management network interface on all nodes where rabbitmq runs.
Connect storage network on node-1.domain.tld node - enables storage
network interface on node-1.domain.tld.

Extended API

1. Service actions
Get a service and restart it:
cloud_management = os_faults.connect(cloud_config)
service = cloud_management.get_service(name='glance-api')
service.restart()

Available actions:

start - start Service
terminate - terminate Service gracefully
restart - restart Service
kill - terminate Service abruptly
unplug - unplug Service out of network
plug - plug Service into network

2. Container actions
Get a container and restart it:
cloud_management = os_faults.connect(cloud_config)
container = cloud_management.get_container(name='neutron_api')
container.restart()

Available actions:

start - start Container
terminate - terminate Container gracefully
restart - restart Container

3. Node actions
Get all nodes in the cloud and reboot them:
nodes = cloud_management.get_nodes()
nodes.reboot()

Available actions:

reboot - reboot all nodes gracefully
poweroff - power off all nodes abruptly
reset - reset (cold restart) all nodes
disconnect - disable network with the specified name on all nodes
connect - enable network with the specified name on all nodes

4. Operate with nodes
Get all nodes where a service runs, pick one of them and reset:
nodes = service.get_nodes()
one = nodes.pick()
one.reset()
Get nodes where l3-agent runs and disable the management network on them:
fqdns = neutron.l3_agent_list_hosting_router(router_id)
nodes = cloud_management.get_nodes(fqdns=fqdns)
nodes.disconnect(network_name='management')

5. Operate with services
Restart a service on a single node:
service = cloud_management.get_service(name='keystone')
nodes = service.get_nodes().pick()
service.restart(nodes)

6. Operate with containers
Terminate a container on a random node:
container = cloud_management.get_container(name='neutron_ovs_agent')
nodes = container.get_nodes().pick()
container.restart(nodes)

License notes
Ansible is distributed under GPL-3.0 license and thus all programs
that link with its code are subject to GPL restrictions [1].
However these restrictions are not applied to os-faults library
since it invokes Ansible as process [2][3].
Ansible modules are provided with Apache license (compatible to GPL) [4].
Those modules import part of Ansible runtime (modules API) and executed
on remote hosts. os-faults library does not import these module
neither static nor dynamic.

[1] https://www.gnu.org/licenses/gpl-faq.html#GPLModuleLicense
[2] https://www.gnu.org/licenses/gpl-faq.html#GPLPlugins
[3] https://www.gnu.org/licenses/gpl-faq.html#MereAggregation
[4] https://www.apache.org/licenses/GPL-compatibility.html