bitnami/bitnami-docker-postgresql-repmgr

Bitnami Docker Image for PostgreSQL with Replication Manager

In order to unify the approaches followed for Bitnami containers and Bitnami Helm charts, we are moving the different bitnami/bitnami-docker-<container> repositories to a single monorepo bitnami/containers. Please follow bitnami/containers to keep you updated about the latest Bitnami images.

More information here: https://blog.bitnami.com/2022/07/new-source-of-truth-bitnami-containers.html

PostgreSQL HA packaged by Bitnami

What is PostgreSQL HA?

This PostgreSQL cluster solution includes the PostgreSQL replication manager, an open-source tool for managing replication and failover on PostgreSQL clusters.

Overview of PostgreSQL HA

Trademarks: This software listing is packaged by Bitnami. The respective trademarks mentioned in the offering are owned by the respective companies, and use of them does not imply any affiliation or endorsement.

TL;DR

$ docker run --name postgresql-repmgr bitnami/postgresql-repmgr:latest

Docker Compose

$ curl -sSL https://raw.githubusercontent.com/bitnami/bitnami-docker-postgresql-repmgr/master/docker-compose.yml > docker-compose.yml
$ docker-compose up -d

You can find the default credentials and available configuration options in the Environment Variables section.

Why use Bitnami Images?

• Bitnami closely tracks upstream source changes and promptly publishes new versions of this image using our automated systems.
• With Bitnami images the latest bug fixes and features are available as soon as possible.
• Bitnami containers, virtual machines and cloud images use the same components and configuration approach - making it easy to switch between formats based on your project needs.
• All our images are based on minideb a minimalist Debian based container image which gives you a small base container image and the familiarity of a leading Linux distribution.
• All Bitnami images available in Docker Hub are signed with Docker Content Trust (DCT). You can use DOCKER_CONTENT_TRUST=1 to verify the integrity of the images.
• Bitnami container images are released on a regular basis with the latest distribution packages available.

Why use a non-root container?

Non-root container images add an extra layer of security and are generally recommended for production environments. However, because they run as a non-root user, privileged tasks are typically off-limits. Learn more about non-root containers in our docs.

How to deploy Postgresql-repmgr in Kubernetes?

Deploying Bitnami applications as Helm Charts is the easiest way to get started with our applications on Kubernetes. Read more about the installation in the Bitnami PostgreSQL HA Chart GitHub repository.

Bitnami containers can be used with Kubeapps for deployment and management of Helm Charts in clusters.

Supported tags and respective Dockerfile links

Learn more about the Bitnami tagging policy and the difference between rolling tags and immutable tags in our documentation page.

• 14, 14-debian-11, 14.4.0, 14.4.0-debian-11-r16, latest (14/debian-11/Dockerfile)
• 13, 13-debian-11, 13.7.0, 13.7.0-debian-11-r22 (13/debian-11/Dockerfile)
• 12, 12-debian-11, 12.11.0, 12.11.0-debian-11-r19 (12/debian-11/Dockerfile)
• 11, 11-debian-11, 11.16.0, 11.16.0-debian-11-r21 (11/debian-11/Dockerfile)
• 10, 10-debian-11, 10.21.0, 10.21.0-debian-11-r21 (10/debian-11/Dockerfile)

Subscribe to project updates by watching the bitnami/postgresql-repmgr GitHub repo.

Get this image

The recommended way to get the Bitnami PostgreSQL HA Docker Image is to pull the prebuilt image from the Docker Hub Registry.

$ docker pull bitnami/postgresql-repmgr:latest

To use a specific version, you can pull a versioned tag. You can view the list of available versions in the Docker Hub Registry.

$ docker pull bitnami/postgresql-repmgr:[TAG]

If you wish, you can also build the image yourself.

$ docker build -t bitnami/postgresql-repmgr:latest 'https://github.com/bitnami/bitnami-docker-postgresql-repmgr.git#master:14/debian-11'

Persisting your application

If you remove the container all your data will be lost, and the next time you run the image the database will be reinitialized. To avoid this loss of data, you should mount a volume that will persist even after the container is removed.

For persistence you should mount a directory at the /bitnami/postgresql path. If the mounted directory is empty, it will be initialized on the first run.

$ docker run \
    -v /path/to/postgresql-repmgr-persistence:/bitnami/postgresql \
    bitnami/postgresql-repmgr:latest

The docker-compose.yml file present in this repository already configures persistence.

NOTE: As this is a non-root container, the mounted files and directories must have the proper permissions for the UID 1001.

Connecting to other containers

Using Docker container networking, a PostgreSQL server running inside a container can easily be accessed by your application containers and vice-versa.

Containers attached to the same network can communicate with each other using the container name as the hostname.

Using the Command Line

In this example, we will create a PostgreSQL client instance that will connect to the server instance that is running on the same docker network as the client.

Step 1: Create a network

$ docker network create my-network --driver bridge

Step 2: Launch the postgresql-repmgr container within your network

Use the --network <NETWORK> argument to the docker run command to attach the container to the my-network network.

$ docker run --detach --rm --name pg-0 \
  --network my-network \
  --env REPMGR_PARTNER_NODES=pg-0 \
  --env REPMGR_NODE_NAME=pg-0 \
  --env REPMGR_NODE_NETWORK_NAME=pg-0 \
  --env REPMGR_PRIMARY_HOST=pg-0 \
  --env REPMGR_PASSWORD=repmgrpass \
  --env POSTGRESQL_PASSWORD=secretpass \
  bitnami/postgresql-repmgr:latest

Step 3: Launch your PostgreSQL client instance

Finally we create a new container instance to launch the PostgreSQL client and connect to the server created in the previous step:

$ docker run -it --rm \
  --network my-network \
  bitnami/postgresql:10 \
  psql -h pg-0 -U postgres

Using Docker Compose

When not specified, Docker Compose automatically sets up a new network and attaches all deployed services to that network. However, we will explicitly define a new bridge network named my-network. In this example we assume that you want to connect to the PostgreSQL server from your own custom application image which is identified in the following snippet by the service name myapp.

version: '2'

networks:
  my-network:
    driver: bridge

services:
  pg-0:
    image: 'bitnami/postgresql-repmgr:latest'
    networks:
      - my-network
    environment:
      - POSTGRESQL_PASSWORD=custompassword
      - REPMGR_PASSWORD=repmgrpassword
      - REPMGR_PRIMARY_HOST=pg-0
      - REPMGR_NODE_NETWORK_NAME=pg-0
      - REPMGR_NODE_NAME=pg-0
      - REPMGR_PARTNER_NODES=pg-0
  myapp:
    image: 'YOUR_APPLICATION_IMAGE'
    networks:
      - my-network

IMPORTANT:

1. Please update the YOUR_APPLICATION_IMAGE_ placeholder in the above snippet with your application image
2. In your application container, use the hostname pg-0 to connect to the PostgreSQL server

Launch the containers using:

$ docker-compose up -d

Configuration

Initializing a new instance

When the container is executed for the first time, it will execute the files with extensions .sh, .sql and .sql.gz located at /docker-entrypoint-initdb.d.

In order to have your custom files inside the docker image you can mount them as a volume.

Setting the root and repmgr passwords on first run

In the above commands you may have noticed the use of the POSTGRESQL_PASSWORD and REPMGR_PASSWORD environment variables. Passing the POSTGRESQL_PASSWORD environment variable when running the image for the first time will set the password of the postgres user to the value of POSTGRESQL_PASSWORD (or the content of the file specified in POSTGRESQL_PASSWORD_FILE). In the same way, passing the REPMGR_PASSWORD environment variable sets the password of the repmgr user to the value of REPMGR_PASSWORD (or the content of the file specified in REPMGR_PASSWORD_FILE).

$ docker run --name pg-0 --env REPMGR_PASSWORD=repmgrpass --env POSTGRESQL_PASSWORD=secretpass bitnami/postgresql-repmgr:latest

or by modifying the docker-compose.yml file present in this repository:

...
services:
  pg-0:
  ...
    environment:
-      - POSTGRESQL_PASSWORD=adminpassword
+      - POSTGRESQL_PASSWORD=password123
-      - REPMGR_PASSWORD=repmgrpassword
+      - REPMGR_PASSWORD=password123
  ...
  pg-1:
  ...
  environment:
-      - POSTGRESQL_PASSWORD=adminpassword
+      - POSTGRESQL_PASSWORD=password123
-      - REPMGR_PASSWORD=repmgrpassword
+      - REPMGR_PASSWORD=password123
...

Note! Both postgres and repmgr users are superusers and have full administrative access to the PostgreSQL database.

Refer to Creating a database user on first run if you want to set an unprivileged user and a password for the postgres user.

Creating a database on first run

By passing the POSTGRESQL_DATABASE environment variable when running the image for the first time, a database will be created. This is useful if your application requires that a database already exists, saving you from having to manually create the database using the PostgreSQL client.

$ docker run --name pg-0 --env POSTGRESQL_DATABASE=my_database bitnami/postgresql-repmgr:latest

Creating a database user on first run

You can also create a restricted database user that only has permissions for the database created with the POSTGRESQL_DATABASE environment variable. To do this, provide the POSTGRESQL_USERNAME environment variable.

$ docker run --name pg-0 --env POSTGRESQL_USERNAME=my_user --env POSTGRESQL_PASSWORD=password123 --env POSTGRESQL_DATABASE=my_database bitnami/postgresql-repmgr:latest

The docker-compose.yml file present in this repository already configures this setup.

Note! When POSTGRESQL_USERNAME is specified, the postgres user is not assigned a password and as a result you cannot login remotely to the PostgreSQL server as the postgres user. If you still want to have access with the user postgres, please set the POSTGRESQL_POSTGRES_PASSWORD environment variable (or the content of the file specified in POSTGRESQL_POSTGRES_PASSWORD_FILE).

Setting up a HA PostgreSQL cluster with streaming replication and repmgr

A HA PostgreSQL cluster with Streaming replication and repmgr can easily be setup with the Bitnami PostgreSQL HA Docker Image using the following environment variables:

• POSTGRESQL_PASSWORD: Password for postgres user. No defaults.
• POSTGRESQL_PASSWORD_FILE: Path to a file that contains the postgres user password. This will override the value specified in POSTGRESQL_PASSWORD. No defaults.
• REPMGR_USERNAME: Username for repmgr user. Defaults to repmgr.
• REPMGR_PASSWORD_FILE: Path to a file that contains the repmgr user password. This will override the value specified in REPMGR_PASSWORD. No defaults.
• REPMGR_PASSWORD: Password for repmgr user. No defaults.
• REPMGR_USE_PASSFILE: Configure repmgr to use passfile and PGPASSFILE instead of plain-text password in its configuration.
• REPMGR_PASSFILE_PATH: Location of the passfile, if it doesn't exist it will be created using REPMGR credentials.
• REPMGR_PRIMARY_HOST: Hostname of the initial primary node. No defaults.
• REPMGR_PARTNER_NODES: Comma separated list of partner nodes in the cluster. No defaults.
• REPMGR_NODE_NAME: Node name. No defaults.
• REPMGR_NODE_NETWORK_NAME: Node hostname. No defaults.
• REPMGR_PGHBA_TRUST_ALL: This will set the auth-method in the generated pg_hba.conf. Set it to yes only if you are using pgpool with LDAP authentication. Default to no.

In a HA PostgreSQL cluster you can have one primary and zero or more standby nodes. The primary node is in read-write mode, while the standby nodes are in read-only mode. For best performance its advisable to limit the reads to the standby nodes.

NOTE: REPMGR_USE_PASSFILE and REPMGR_PASSFILE_PATH will be ignored for Postgresql prior to version 9.6.

When mounting an external passfile using REPMGR_PASSFILE_PATH, it is necessary to also configure REPMGR_PASSWORD and REPMGR_USERNAME accordingly.

Step 1: Create a network

$ docker network create my-network --driver bridge

Step 2: Create the initial primary node

The first step is to start the initial primary node:

$ docker run --detach --name pg-0 \
  --network my-network \
  --env REPMGR_PARTNER_NODES=pg-0,pg-1 \
  --env REPMGR_NODE_NAME=pg-0 \
  --env REPMGR_NODE_NETWORK_NAME=pg-0 \
  --env REPMGR_PRIMARY_HOST=pg-0 \
  --env REPMGR_PASSWORD=repmgrpass \
  --env POSTGRESQL_PASSWORD=secretpass \
  bitnami/postgresql-repmgr:latest

Step 3: Create a standby node

Next we start a standby node:

$ docker run --detach --name pg-1 \
  --network my-network \
  --env REPMGR_PARTNER_NODES=pg-0,pg-1 \
  --env REPMGR_NODE_NAME=pg-1 \
  --env REPMGR_NODE_NETWORK_NAME=pg-1 \
  --env REPMGR_PRIMARY_HOST=pg-0 \
  --env REPMGR_PASSWORD=repmgrpass \
  --env POSTGRESQL_PASSWORD=secretpass \
  bitnami/postgresql-repmgr:latest

With these three commands you now have a two node PostgreSQL primary-standby streaming replication cluster up and running. You can scale the cluster by adding/removing standby nodes without incurring any downtime.

Note: The cluster replicates the primary in its entirety, which includes all users and databases.

If the master goes down, repmgr will ensure any of the standby nodes takes the primary role, guaranteeing high availability.

Note: The configuration of the other nodes in the cluster needs to be updated so that they are aware of them. This would require you to restart the old nodes adapting the REPMGR_PARTNER_NODES environment variable.

With Docker Compose the HA PostgreSQL cluster can be setup using the docker-compose.yml file present in this repository:

$ curl -sSL https://raw.githubusercontent.com/bitnami/bitnami-docker-postgresql-repmgr/master/docker-compose.yml > docker-compose.yml
$ docker-compose up -d

Securing PostgreSQL traffic

PostgreSQL supports the encryption of connections using the SSL/TLS protocol. Should you desire to enable this optional feature, you may use the following environment variables to configure the application:

• POSTGRESQL_ENABLE_TLS: Whether to enable TLS for traffic or not. Defaults to no.
• POSTGRESQL_TLS_CERT_FILE: File containing the certificate file for the TLS traffic. No defaults.
• POSTGRESQL_TLS_KEY_FILE: File containing the key for certificate. No defaults.
• POSTGRESQL_TLS_CA_FILE: File containing the CA of the certificate. If provided, PostgreSQL will authenticate TLS/SSL clients by requesting them a certificate (see ref). No defaults.
• POSTGRESQL_TLS_CRL_FILE: File containing a Certificate Revocation List. No defaults.
• POSTGRESQL_TLS_PREFER_SERVER_CIPHERS: Whether to use the server's TLS cipher preferences rather than the client's. Defaults to yes.

When enabling TLS, PostgreSQL will support both standard and encrypted traffic by default, but prefer the latter. Below there are some examples on how to quickly set up TLS traffic:

1. Using docker run

   $ docker run \
       -v /path/to/certs:/opt/bitnami/postgresql/certs \
       -e POSTGRESQL_ENABLE_TLS=yes \
       -e POSTGRESQL_TLS_CERT_FILE=/opt/bitnami/postgresql/certs/postgres.crt \
       -e POSTGRESQL_TLS_KEY_FILE=/opt/bitnami/postgresql/certs/postgres.key \
       bitnami/postgresql-repmgr:latest

2. Modifying the docker-compose.yml file present in this repository:

   services:
     pg-0:
     ...
       environment:
         ...
         - POSTGRESQL_ENABLE_TLS=yes
         - POSTGRESQL_TLS_CERT_FILE=/opt/bitnami/postgresql/certs/postgres.crt
         - POSTGRESQL_TLS_KEY_FILE=/opt/bitnami/postgresql/certs/postgres.key
       ...
       volumes:
         ...
         - /path/to/certs:/opt/bitnami/postgresql/certs
     ...

Alternatively, you may also provide this configuration in your custom configuration file.

Configuration file

The image looks for the repmgr.conf, postgresql.conf and pg_hba.conf files in /opt/bitnami/repmgr/conf/ and /opt/bitnami/postgresql/conf/. You can mount a volume at /bitnami/repmgr/conf/ and copy/edit the configuration files in the /path/to/custom-conf/. The default configurations will be populated to the conf/ directories if /bitnami/repmgr/conf/ is empty.

/path/to/custom-conf/
└── postgresql.conf

As the PostgreSQL with Replication manager image is non-root, you need to set the proper permissions to the mounted directory in your host:

$ sudo chgrp -R root /path/to/custom-conf/
$ sudo chmod -R g+rwX /path/to/custom-conf/

Step 1: Run the PostgreSQL image

Run the PostgreSQL image, mounting a directory from your host.

$ docker run --name pg-0 \
    -v /path/to/custom-conf/:/bitnami/repmgr/conf/ \
    bitnami/postgresql-repmgr:latest

or using Docker Compose:

version: '2'

services:
  pg-0:
    image: bitnami/postgresql-repmgr:latest
    ports:
      - '5432:5432'
    volumes:
      - /path/to/custom-conf/:/bitnami/repmgr/conf/
  pg-1:
    image: bitnami/postgresql-repmgr:latest
    ports:
      - '5432:5432'
    volumes:
      - /path/to/custom-conf/:/bitnami/repmgr/conf/

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

vi /path/to/custom-conf/postgresql.conf

Step 3: Restart PostgreSQL

After changing the configuration, restart your PostgreSQL container for changes to take effect.

$ docker restart pg-0

or using Docker Compose:

$ docker-compose restart pg-0
$ docker-compose restart pg-1

Refer to the server configuration manual for the complete list of configuration options.

Allow settings to be loaded from files other than the default postgresql.conf

Apart of using a custom repmgr.conf, postgresql.conf or pg_hba.conf, you can include files ending in .conf from the conf.d directory in the volume at /bitnami/postgresql/conf/. For this purpose, the default postgresql.conf contains the following section:

##------------------------------------------------------------------------------
## CONFIG FILE INCLUDES
##------------------------------------------------------------------------------

## These options allow settings to be loaded from files other than the
## default postgresql.conf.

include_dir = 'conf.d'  # Include files ending in '.conf' from directory 'conf.d'

If you are using your custom postgresql.conf, you should create (or uncomment) the above section in your config file, in this case the structure should be something like

/path/to/custom-conf/
└── postgresql.conf
/path/to/extra-custom-conf/
└── extended.conf

Remember to set the proper permissions to the mounted directory in your host:

$ sudo chgrp -R root /path/to/extra-custom-conf/
$ sudo chmod -R g+rwX /path/to/extra-custom-conf/

Step 1: Run the PostgreSQL image

Run the PostgreSQL image, mounting a directory from your host.

$ docker run --name pg-0 \
    -v /path/to/extra-custom-conf/:/bitnami/postgresql/conf/conf.d/ \
    -v /path/to/custom-conf/:/bitnami/repmgr/conf/ \
    bitnami/postgresql-repmgr:latest

or using Docker Compose:

version: '2'

services:
  pg-0:
    image: bitnami/postgresql-repmgr:latest
    ports:
      - '5432:5432'
    volumes:
      - /path/to/extra-custom-conf/:/bitnami/postgresql/conf/conf.d/
      - /path/to/custom-conf/:/bitnami/repmgr/conf/
  pg-1:
    image: bitnami/postgresql-repmgr:latest
    ports:
      - '5432:5432'
    volumes:
      - /path/to/extra-custom-conf/:/bitnami/postgresql/conf/conf.d/
      - /path/to/custom-conf/:/bitnami/repmgr/conf/

Step 2: Edit the configuration

Edit the configuration on your host using your favorite editor.

vi /path/to/extra-custom-conf/extended.conf

Step 3: Restart PostgreSQL

After changing the configuration, restart your PostgreSQL container for changes to take effect.

$ docker restart pg-0

or using Docker Compose:

$ docker-compose restart pg-0
$ docker-compose restart pg-1

Environment variables

Please see the list of environment variables available in the Bitnami PostgreSQL HA container in the next table:

Environment Variable	Default value
REPMGR_NODE_ID	nil
REPMGR_NODE_ID_START_SEED	1000
REPMGR_NODE_NAME	nil
REPMGR_NODE_NETWORK_NAME	nil
REPMGR_NODE_PRIORITY	100
REPMGR_PARTNER_NODES	nil
REPMGR_PRIMARY_HOST	nil
REPMGR_NODE_LOCATION	default
REPMGR_PRIMARY_PORT	5432
REPMGR_PORT_NUMBER	5432
REPMGR_LOG_LEVEL	NOTICE
REPMGR_START_OPTIONS	nil
REPMGR_CONNECT_TIMEOUT	5
REPMGR_RECONNECT_ATTEMPTS	3
REPMGR_RECONNECT_INTERVAL	5
REPMGR_USE_REPLICATION_SLOTS	1
REPMGR_MASTER_RESPONSE_TIMEOUT	20
REPMGR_DEGRADED_MONITORING_TIMEOUT	5
REPMGR_USERNAME	repmgr
REPMGR_DATABASE	repmgr
REPMGR_PASSWORD	nil
REPMGR_PASSWORD_FILE	nil
REPMGR_FENCE_OLD_PRIMARY	no
REPMGR_CHILD_NODES_CHECK_INTERVAL	5
REPMGR_CHILD_NODES_CONNECTED_MIN_COUNT	1
REPMGR_CHILD_NODES_DISCONNECT_TIMEOUT	30
REPMGR_USE_PASSFILE	nil
POSTGRESQL_USERNAME	postgres
POSTGRESQL_DATABASE	nil
POSTGRESQL_PASSWORD	nil
POSTGRESQL_PASSWORD_FILE	nil
POSTGRESQL_POSTGRES_PASSWORD	nil
POSTGRESQL_POSTGRES_PASSWORD_FILE	nil
POSTGRESQL_PORT_NUMBER	5432
POSTGRESQL_INITDB_ARGS	nil
POSTGRESQL_PGCTLTIMEOUT	60
POSTGRESQL_SHUTDOWN_MODE	fast
POSTGRESQL_ENABLE_TLS	no
POSTGRESQL_TLS_CERT_FILE	nil
POSTGRESQL_TLS_KEY_FILE	nil
POSTGRESQL_TLS_CA_FILE	nil
POSTGRESQL_TLS_CRL_FILE	nil
POSTGRESQL_TLS_PREFER_SERVER_CIPHERS	yes

Logging

The Bitnami PostgreSQL HA Docker image sends the container logs to stdout. To view the logs:

$ docker logs pg-0

You can configure the containers logging driver using the --log-driver option if you wish to consume the container logs differently. In the default configuration docker uses the json-file driver.

Maintenance

Upgrade this image

Bitnami provides up-to-date versions of PostgreSQL HA, including security patches, soon after they are made upstream. We recommend that you follow these steps to upgrade your container.

Step 1: Get the updated image

$ docker pull bitnami/postgresql-repmgr:latest

or if you're using Docker Compose, update the value of the image property to bitnami/postgresql-repmgr:latest.

Step 2: Stop the running container

Stop the currently running container using the command

$ docker stop pg-0

or using Docker Compose:

$ docker-compose stop pg-0
$ docker-compose stop pg-1

Next, take a snapshot of the persistent volume /path/to/postgresql-persistence using:

$ rsync -a /path/to/postgresql-persistence /path/to/postgresql-persistence.bkp.$(date +%Y%m%d-%H.%M.%S)

Step 3: Remove the currently running container

$ docker rm -v pg-0

or using Docker Compose:

$ docker-compose rm -v pg-0
$ docker-compose rm -v pg-1

Step 4: Run the new image

Re-create your container from the new image.

$ docker run --name pg-0 bitnami/postgresql-repmgr:latest

or using Docker Compose:

$ docker-compose up pg-0
$ docker-compose up pg-1

Notable Changes

9.6.16-centos-7-r71, 10.11.0-centos-7-r71, 11.6.0-centos-7-r67, and 12.1.0-centos-7-r67

• 9.6.16-centos-7-r71, 10.11.0-centos-7-r71, 11.6.0-centos-7-r67, and 12.1.0-centos-7-r67 are considered the latest images based on CentOS.
• Standard supported distros: Debian & OEL.

9.6.15-r18, 9.6.15-ol-7-r23, 9.6.15-centos-7-r23, 10.10.0-r18, 10.10.0-ol-7-r23, 10.10.0-centos-7-r23, 11.5.0-r19, 11.5.0-centos-7-r23, 11.5.0-ol-7-r23

• Adds Postgis extension to postgresql, version 2.3.x to Postgresiql 9.6 and version 2.5 to 10, 11 and 12.

Contributing

We'd love for you to contribute to this container. You can request new features by creating an issue, or submit a pull request with your contribution.

Issues

If you encountered a problem running this container, you can file an issue. For us to provide better support, be sure to include the following information in your issue:

• Host OS and version
• Docker version (docker version)
• Output of docker info
• Version of this container
• The command you used to run the container, and any relevant output you saw (masking any sensitive information)

License

Copyright © 2022 Bitnami

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.