https://raw.githubusercontent.com/ansible/ansible/stable-2.0/CHANGELOG.md からの抜粋

Ansible Changes By Release

2.0 "Over the Hills and Far Away" - ACTIVE DEVELOPMENT

2.1 TBD - ACTIVE DEVELOPMENT

New Modules:

cloudstack: cs_volume

New Filters:

extract

2.0 "Over the Hills and Far Away"

Major Changes:

Releases are now named after Led Zeppelin songs, 1.9 will be the last Van Halen named release.
リリース 2.0 "Over the Hills and Far Away"はLed Zeppelinの曲にちなんで付けられた（それまではVan Halenだった）
The new block/rescue/always directives allow for making task blocks and exception-like semantics
新しいタスクブロックを作るための block/rescue/always というディレクティブが追加された
New strategy plugins (e.g. free) allow control over the flow of task execution per play. The default (linear) will be the same as before.
Improved error handling, with more detailed parser messages. General exception handling and display has been revamped.
Task includes are now evaluated during execution, allowing more dynamic includes and options. Play includes are unchanged both still use the include directive.
"with_" loops can now be used with task includes since they are dynamic.
Callback, connection, cache and lookup plugin APIs have changed. Existing plugins might require modification to work with the new versions.
Callbacks are now shipped in the active directory and don't need to be copied, just whitelisted in ansible.cfg.
Many API changes. Those integrating directly with Ansible's API will encounter breaking changes, but the new API is much easier to use and test.
Settings are now more inheritable; what you set at play, block or role will be automatically inherited by the contained tasks.
This allows for new features to automatically be settable at all levels, previously we had to manually code this.
Vars are now settable at play, block, role and task level with the vars directive and scoped to the tasks contained.
Template code now retains types for bools and numbers instead of turning them into strings.
If you need the old behaviour, quote the value and it will get passed around as a string
Empty variables and variables set to null in yaml will no longer be converted to empty strings. They will retain the value of None.
To go back to the old behaviour, you can override the null_representation setting to an empty string in your config file or
by setting the ANSIBLE_NULL_REPRESENTATION environment variable.
Added meta: refresh_inventory to force rereading the inventory in a play.
This re-executes inventory scripts, but does not force them to ignore any cache they might use.
New delegate_facts directive, a boolean that allows you to apply facts to the delegated host (true/yes) instead of the inventory_hostname (no/false) which is the default and previous behaviour.
local connections now work with 'su' as a privilege escalation method
New ssh configuration variables(ansible_ssh_common_args, ansible_ssh_extra_args) can be used to configure a
per-group or per-host ssh ProxyCommand or set any other ssh options.
ansible_ssh_extra_args is used to set options that are accepted only by ssh (not sftp or scp, which have their own analogous settings).
ansible-pull can now verify the code it runs when using git as a source repository, using git's code signing and verification features.

Backslashes used when specifying parameters in jinja2 expressions in YAML dicts sometimes needed to be escaped twice.
This has been fixed so that escaping once works. Here's an example of how playbooks need to be modified:

# Syntax in 1.9.x
- debug:
    msg: "{{ 'test1_junk 1\\\\3' | regex_replace('(.*)_junk (.*)', '\\\\1 \\\\2') }}"
# Syntax in 2.0.x
- debug:
    msg: "{{ 'test1_junk 1\\3' | regex_replace('(.*)_junk (.*)', '\\1 \\2') }}"

# Output:
"msg": "test1 1\\3"

When a string with a trailing newline was specified in the playbook via yaml
dict format, the trailing newline was stripped. When specified in key=value
format the trailing newlines were kept. In v2, both methods of specifying the
string will keep the trailing newlines. If you relied on the trailing
newline being stripped you can change your playbook like this:
```
# Syntax in 1.9.2
vars:
  message: >
    Testing
    some things
tasks:
- debug:
    msg: "{{ message }}"

# Syntax in 2.0.x
vars:
  old_message: >
    Testing
    some things
  message: "{{ old_messsage[:-1] }}"
- debug:
    msg: "{{ message }}"
# Output
"msg": "Testing some things"
```
When specifying complex args as a variable, the variable must use the full jinja2
variable syntax ('{{var_name}}') - bare variable names there are no longer accepted.
In fact, even specifying args with variables has been deprecated, and will not be
allowed in future versions:
```
---
- hosts: localhost
  connection: local
  gather_facts: false
  vars:
    my_dirs:
      - { path: /tmp/3a, state: directory, mode: 0755 }
      - { path: /tmp/3b, state: directory, mode: 0700 }
  tasks:
    - file:
      args: "{{item}}"
      with_items: my_dirs
```
The bigip* networking modules have a new parameter, validate_certs. When
True (the default) the module will validate any hosts it connects to against
the TLS certificates it presents when run on new enough python versions. If
the python version is too old to validate certificates or you used certificates
that cannot be validated against available CAs you will need to add
validate_certs=no to your playbook for those tasks.

Plugins

Rewritten dnf module that should be faster and less prone to encountering bugs in cornercases
WinRM connection plugin passes all vars named ansible_winrm_* to the underlying pywinrm client. This allows, for instance, ansible_winrm_server_cert_validation=ignore to be used with newer versions of pywinrm to disable certificate validation on Python 2.7.9+.
WinRM connection plugin put_file is significantly faster and no longer has file size limitations.

Deprecated Modules (new ones in parens):

ec2_ami_search (ec2_ami_find)
quantum_network (os_network)
glance_image
nova_compute (os_server)
quantum_floating_ip (os_floating_ip)
quantum_router (os_router)
quantum_router_gateway (os_router)
quantum_router_interface (os_router)

New Modules:

amazon: ec2_ami_copy
amazon: ec2_ami_find
amazon: ec2_elb_facts
amazon: ec2_eni
amazon: ec2_eni_facts
amazon: ec2_remote_facts
amazon: ec2_vpc_igw
amazon: ec2_vpc_net
amazon: ec2_vpc_route_table
amazon: ec2_vpc_route_table_facts
amazon: ec2_vpc_subnet
amazon: ec2_vpc_subnet_facts
amazon: ec2_win_password
amazon: ecs_cluster
amazon: ecs_task
amazon: ecs_taskdefinition
amazon: elasticache_subnet_group_facts
amazon: iam
amazon: iam_cert
amazon: iam_policy
amazon: route53_facts
amazon: route53_health_check
amazon: route53_zone
amazon: sts_assume_role
amazon: s3_bucket
amazon: s3_lifecycle
amazon: s3_logging
amazon: sqs_queue
amazon: sns_topic
amazon: sts_assume_role
apk
bigip_gtm_wide_ip
bundler
centurylink: clc_aa_policy
centurylink: clc_alert_policy
centurylink: clc_blueprint_package
centurylink: clc_firewall_policy
centurylink: clc_group
centurylink: clc_loadbalancer
centurylink: clc_modify_server
centurylink: clc_publicip
centurylink: clc_server
centurylink: clc_server_snapshot
circonus_annotation
consul
consul_acl
consul_kv
consul_session
cloudtrail
cloudstack: cs_account
cloudstack: cs_affinitygroup
cloudstack: cs_domain
cloudstack: cs_facts
cloudstack: cs_firewall
cloudstack: cs_iso
cloudstack: cs_instance
cloudstack: cs_instancegroup
cloudstack: cs_ip_address
cloudstack: cs_loadbalancer_rule
cloudstack: cs_loadbalancer_rule_member
cloudstack: cs_network
cloudstack: cs_portforward
cloudstack: cs_project
cloudstack: cs_sshkeypair
cloudstack: cs_securitygroup
cloudstack: cs_securitygroup_rule
cloudstack: cs_staticnat
cloudstack: cs_template
cloudstack: cs_user
cloudstack: cs_vmsnapshot
cronvar
datadog_monitor
deploy_helper
docker: docker_login
dpkg_selections
elasticsearch_plugin
expect
find
google: gce_tag
hall
ipify_facts
iptables
libvirt: virt_net
libvirt: virt_pool
maven_artifact
openstack: os_auth
openstack: os_client_config
openstack: os_image
openstack: os_image_facts
openstack: os_floating_ip
openstack: os_ironic
openstack: os_ironic_node
openstack: os_keypair
openstack: os_network
openstack: os_network_facts
openstack: os_nova_flavor
openstack: os_object
openstack: os_port
openstack: os_project
openstack: os_router
openstack: os_security_group
openstack: os_security_group_rule
openstack: os_server
openstack: os_server_actions
openstack: os_server_facts
openstack: os_server_volume
openstack: os_subnet
openstack: os_subnet_facts
openstack: os_user
openstack: os_user_group
openstack: os_volume
openvswitch_db.
osx_defaults
pagerduty_alert
pam_limits
pear
profitbricks: profitbricks
profitbricks: profitbricks_datacenter
profitbricks: profitbricks_nic
profitbricks: profitbricks_volume
profitbricks: profitbricks_volume_attachments
profitbricks: profitbricks_snapshot
proxmox: proxmox
proxmox: proxmox_template
puppet
pushover
pushbullet
rax: rax_clb_ssl
rax: rax_mon_alarm
rax: rax_mon_check
rax: rax_mon_entity
rax: rax_mon_notification
rax: rax_mon_notification_plan
rabbitmq_binding
rabbitmq_exchange
rabbitmq_queue
selinux_permissive
sendgrid
sensu_check
sensu_subscription
seport
slackpkg
solaris_zone
taiga_issue
vertica_configuration
vertica_facts
vertica_role
vertica_schema
vertica_user
vmware: vca_fw
vmware: vca_nat
vmware: vmware_cluster
vmware: vmware_datacenter
vmware: vmware_dns_config
vmware: vmware_dvs_host
vmware: vmware_dvs_portgroup
vmware: vmware_dvswitch
vmware: vmware_host
vmware: vmware_migrate_vmk
vmware: vmware_portgroup
vmware: vmware_target_canonical_facts
vmware: vmware_vm_facts
vmware: vmware_vm_vss_dvs_migrate
vmware: vmware_vmkernel
vmware: vmware_vmkernel_ip_config
vmware: vmware_vsan_cluster
vmware: vmware_vswitch
vmware: vsphere_copy
webfaction_app
webfaction_db
webfaction_domain
webfaction_mailbox
webfaction_site
win_acl
win_dotnet_ngen
win_environment
win_firewall_rule
win_iis_virtualdirectory
win_iis_webapplication
win_iis_webapppool
win_iis_webbinding
win_iis_website
win_lineinfile
win_nssm
win_package
win_regedit
win_scheduled_task
win_unzip
win_updates
win_webpicmd
xenserver_facts
zabbix_host
zabbix_hostmacro
zabbix_screen
znode

New Inventory scripts:

cloudstack
fleetctl
openvz
nagios_ndo
nsot
proxmox
rudder
serf

New Lookups:

credstash
hashi_vault
ini
shelvefile

New Filters:

combine

New Connection:

docker: for talking to docker containers on the ansible controller machine without using ssh.

New Callbacks:

logentries: plugin to send play data to logentries service
skippy: same as default but does not display skip messages

Minor changes:

Many more tests. The new API makes things more testable and we took advantage of it.
big_ip modules now support turning off ssl certificate validation (use only for self-signed certificates).
Consolidated code from modules using urllib2 to normalize features, TLS and SNI support.
synchronize module's dest_port parameter now takes precedence over the ansible_ssh_port inventory setting.
Play output is now dynamically sized to terminal with a minimum of 80 coluumns (old default).
vars_prompt and pause are now skipped with a warning if the play is called non interactively (i.e. pull from cron).
Support for OpenBSD's 'doas' privilege escalation method.
Most vault operations can now be done over multilple files.
ansible-vault encrypt/decrypt read from stdin if no other input file is given, and can write to a given --output file (including stdout, '-').
This lets you avoid ever writing sensitive plaintext to disk.
ansible-vault rekey accepts the --new-vault-password-file option.
ansible-vault now preserves file permissions on edit and rekey and defaults to restrictive permissions for other options.
Configuration items defined as paths (local only) now all support shell style interpolations.
Many fixes and new options added to modules, too many to list here.
Now you can see task file and line number when using verbosity of 3 or above.
The [x-y] host range syntax is no longer supported. Note that [0:1] matches two hosts, i.e. the range is inclusive of its endpoints.
We now recommend the Use pattern1,pattern2 to combine host matching patterns.
- The use of ':' as a separator conflicts with IPv6 addresses and host ranges. It will be deprecated in the future.
- The undocumented use of ';' as a separator is now deprecated.
modules and callbacks have been extended to support no_log to avoid data disclosure.
new managed_syslog option has been added to control output to syslog on managed machines, no_log supercsedes this settings.
Lookup, vars and action plugin pathing has been normalized, all now follow the same sequence to find relative files.
We do not ignore the explicitly set login user for ssh when it matches the 'current user' anymore, this allows overriding .ssh/config when it is set
explicitly. Leaving it unset will still use the same user and respect .ssh/config. This also means ansible_ssh_user can now return a None value.
environment variables passed to remote shells now default to 'controller' settings, with fallback to en_us.UTF8 which was the previous default.
add_hosts is much stricter about host name and will prevent invalid names from being added.
ansible-pull now defaults to doing shallow checkouts with git, use --full to return to previous behaviour.
random cows are more random
when: now gets the registered var after the first iteration, making it possible to break out of item loops
Handling of undefined variables has changed. In most places they will now raise an error instead of silently injecting an empty string. Use the default filter if you want to approximate the old behaviour:
```
- debug: msg="The error message was: {{error_code |default('') }}"
```
The yum module's detection of installed packages has been made more robust by
using /usr/bin/rpm in cases where it woud have used repoquery before.
The pip module now properly reports changes when packages are coming from a VCS.
Fixes for retrieving files over https when a CONNECT-only proxy is in the middle.