Merge pull request opencontainers#176 from vbatts/docs-overhaul

Docs overhaul

README.md

@@ -1,17 +1,22 @@
 # Open Container Specifications
 
-This project is where the [Open Container Initiative](http://www.opencontainers.org/) Specifications are written.
-This is a work in progress.
+[Open Container Initiative](http://www.opencontainers.org/) Specifications for standards on Operating System process and application containers.
+
 
 Table of Contents
 
+- [Container Principles](principles.md)
 - [Filesystem Bundle](bundle.md)
-- [Container Configuration](config.md)
-  - [Linux Specific Configuration](config-linux.md)
+- Configuration
+  - [Container Configuration](config.md)
+  - [Container Configuration (Linux-specific)](config-linux.md)
+  - [Runtime Configuration](runtime-config.md)
+  - [Runtime Configuration (Linux-specific)](runtime-config-linux.md)
 - [Runtime and Lifecycle](runtime.md)
+  - [Linux Specific Runtime](runtime-linux.md)
 - [Implementations](implementations.md)
 
-## Use Cases
+# Use Cases
 
 To provide context for users the following section gives example use cases for each part of the spec.
 
@@ -24,58 +29,6 @@ To provide context for users the following section gives example use cases for e
 There is a loose [Road Map](https://github.com/opencontainers/specs/wiki/RoadMap:) on the wiki.
 During the `0.x` series of OCI releases we make no backwards compatibility guarantees and intend to break the schema during this series.
 
-# The 5 principles of Standard Containers
-
-Define a unit of software delivery called a Standard Container.
-The goal of a Standard Container is to encapsulate a software component and all its dependencies in a format that is self-describing and portable, so that any compliant runtime can run it without extra dependencies, regardless of the underlying machine and the contents of the container.
-
-The specification for Standard Containers is straightforward.
-It mostly defines 1) a file format, 2) a set of standard operations, and 3) an execution environment.
-
-A great analogy for this is the shipping container.
-Just like how Standard Containers are a fundamental unit of software delivery, shipping containers are a fundamental unit of physical delivery.
-
-## 1. Standard operations
-
-Just like shipping containers, Standard Containers define a set of STANDARD OPERATIONS.
-Shipping containers can be lifted, stacked, locked, loaded, unloaded and labelled.
-Similarly, Standard Containers can be created, started, and stopped using standard container tools (what this spec is about); copied and snapshotted using standard filesystem tools; and downloaded and uploaded using standard network tools.
-
-## 2. Content-agnostic
-
-Just like shipping containers, Standard Containers are CONTENT-AGNOSTIC: all standard operations have the same effect regardless of the contents.
-A shipping container will be stacked in exactly the same way whether it contains Vietnamese powder coffee or spare Maserati parts.
-Similarly, Standard Containers are started or uploaded in the same way whether they contain a postgres database, a php application with its dependencies and application server, or Java build artifacts.
-
-## 3. Infrastructure-agnostic
-
-Both types of containers are INFRASTRUCTURE-AGNOSTIC: they can be transported to thousands of facilities around the world, and manipulated by a wide variety of equipment.
-A shipping container can be packed in a factory in Ukraine, transported by truck to the nearest routing center, stacked onto a train, loaded into a German boat by an Australian-built crane, stored in a warehouse at a US facility, etc.
-Similarly, a standard container can be bundled on my laptop, uploaded to S3, downloaded, run and snapshotted by a build server at Equinix in Virginia, uploaded to 10 staging servers in a home-made Openstack cluster, then sent to 30 production instances across 3 EC2 regions.
-
-## 4. Designed for automation
-
-Because they offer the same standard operations regardless of content and infrastructure, Standard Containers, just like their physical counterparts, are extremely well-suited for automation.
-In fact, you could say automation is their secret weapon.
-
-Many things that once required time-consuming and error-prone human effort can now be programmed.
-Before shipping containers, a bag of powder coffee was hauled, dragged, dropped, rolled and stacked by 10 different people in 10 different locations by the time it reached its destination.
-1 out of 50 disappeared.
-1 out of 20 was damaged.
-The process was slow, inefficient and cost a fortune - and was entirely different depending on the facility and the type of goods.
-
-Similarly, before Standard Containers, by the time a software component ran in production, it had been individually built, configured, bundled, documented, patched, vendored, templated, tweaked and instrumented by 10 different people on 10 different computers.
-Builds failed, libraries conflicted, mirrors crashed, post-it notes were lost, logs were misplaced, cluster updates were half-broken.
-The process was slow, inefficient and cost a fortune - and was entirely different depending on the language and infrastructure provider.
-
-## 5. Industrial-grade delivery
-
-There are 17 million shipping containers in existence, packed with every physical good imaginable.
-Every single one of them can be loaded onto the same boats, by the same cranes, in the same facilities, and sent anywhere in the World with incredible efficiency.
-It is embarrassing to think that a 30 ton shipment of coffee can safely travel half-way across the World in *less time* than it takes a software team to deliver its code from one datacenter to another sitting 10 miles away.
-
-With Standard Containers we can put an end to that embarrassment, by making INDUSTRIAL-GRADE DELIVERY of software a reality.
-
 # Contributing
 
 Development happens on GitHub for the spec.

bundle.md

@@ -1,4 +1,6 @@
-# Bundle Container Format
+# Bundle
+
+## Container Format
 
 This section defines a format for encoding a container as a *bundle* - a directory organized in a certain way, and containing all the necessary data and metadata for any compliant runtime to perform all standard operations against it.
 See also [OS X application bundles](http://en.wikipedia.org/wiki/Bundle_%28OS_X%29) for a similar use of the term *bundle*.
@@ -14,15 +16,18 @@ A standard container bundle is made of the following 3 parts:
 - One or more content directories
 - A configuration file
 
-# Directory layout
+## Directory layout
 
 A Standard Container bundle is a directory containing all the content needed to load and run a container.
 This includes two configuration files `config.json` and `runtime.json`, and a rootfs directory.
 The `config.json` file contains settings that are host independent and application specific such as security permissions, environment variables and arguments.
 The `runtime.json` file contains settings that are host specific such as memory limits, local device access and mount points.
 The goal is that the bundle can be moved as a unit to another machine and run the same application if `runtime.json` is removed or reconfigured.
 
-The syntax and semantics for `config.json` are described in [this specification](config.md).
+Configuration file syntax and semantics:
+
+* [`config.json`](config.md) (immutable, host independent configuration)
+* [`runtime.json`](runtime-config.md) (mutable, host dependent configuration)
 
 A single `rootfs` directory MUST be in the same directory as the `config.json`.
 The names of the directories may be arbitrary, but users should consider using conventional names as in the example below.

code-of-conduct.md

@@ -2,7 +2,6 @@
 
 Behave as a community member, follow the code of conduct.
 
-
 ## Code of Conduct
 
 The OpenContainers community is made up of a mixture of professionals and volunteers from all over the world.
@@ -36,4 +35,3 @@ By adopting this Code of Conduct, project maintainers commit themselves to fairl
 Thanks to the [Fedora Code of Conduct](https://getfedora.org/code-of-conduct) and [Contributor Covenant](http://contributor-covenant.org) for inspiration and ideas.
 
 Portions of this Code of Conduct are adapted from the Contributor Covenant, version 1.2.0, available at http://contributor-covenant.org/version/1/2/0/
-

config-linux.md

@@ -1,4 +1,4 @@
-# Linux-specific configuration
+# Linux-specific Container Configuration
 
 The Linux container specification uses various kernel features like namespaces, cgroups, capabilities, LSM, and file system jails to fulfill the spec.
 Additional information is needed for Linux over the [default spec configuration](config.md) in order to configure these various kernel features.

config.md

@@ -1,4 +1,4 @@
-# Configuration file
+# Container Configuration file
 
 The container's top-level directory MUST contain a configuration file called `config.json`.
 For now the canonical schema is defined in [config.go](config.go) and [config_linux.go](config_linux.go), but this will be moved to a formal JSON schema over time.

principles.md

@@ -0,0 +1,51 @@
+# The 5 principles of Standard Containers
+
+Define a unit of software delivery called a Standard Container.
+The goal of a Standard Container is to encapsulate a software component and all its dependencies in a format that is self-describing and portable, so that any compliant runtime can run it without extra dependencies, regardless of the underlying machine and the contents of the container.
+
+The specification for Standard Containers is straightforward.
+It mostly defines 1) a file format, 2) a set of standard operations, and 3) an execution environment.
+
+A great analogy for this is the shipping container.
+Just like how Standard Containers are a fundamental unit of software delivery, shipping containers are a fundamental unit of physical delivery.
+
+## 1. Standard operations
+
+Just like shipping containers, Standard Containers define a set of STANDARD OPERATIONS.
+Shipping containers can be lifted, stacked, locked, loaded, unloaded and labelled.
+Similarly, Standard Containers can be created, started, and stopped using standard container tools (what this spec is about); copied and snapshotted using standard filesystem tools; and downloaded and uploaded using standard network tools.
+
+## 2. Content-agnostic
+
+Just like shipping containers, Standard Containers are CONTENT-AGNOSTIC: all standard operations have the same effect regardless of the contents.
+A shipping container will be stacked in exactly the same way whether it contains Vietnamese powder coffee or spare Maserati parts.
+Similarly, Standard Containers are started or uploaded in the same way whether they contain a postgres database, a php application with its dependencies and application server, or Java build artifacts.
+
+## 3. Infrastructure-agnostic
+
+Both types of containers are INFRASTRUCTURE-AGNOSTIC: they can be transported to thousands of facilities around the world, and manipulated by a wide variety of equipment.
+A shipping container can be packed in a factory in Ukraine, transported by truck to the nearest routing center, stacked onto a train, loaded into a German boat by an Australian-built crane, stored in a warehouse at a US facility, etc.
+Similarly, a standard container can be bundled on my laptop, uploaded to S3, downloaded, run and snapshotted by a build server at Equinix in Virginia, uploaded to 10 staging servers in a home-made Openstack cluster, then sent to 30 production instances across 3 EC2 regions.
+
+## 4. Designed for automation
+
+Because they offer the same standard operations regardless of content and infrastructure, Standard Containers, just like their physical counterparts, are extremely well-suited for automation.
+In fact, you could say automation is their secret weapon.
+
+Many things that once required time-consuming and error-prone human effort can now be programmed.
+Before shipping containers, a bag of powder coffee was hauled, dragged, dropped, rolled and stacked by 10 different people in 10 different locations by the time it reached its destination.
+1 out of 50 disappeared.
+1 out of 20 was damaged.
+The process was slow, inefficient and cost a fortune - and was entirely different depending on the facility and the type of goods.
+
+Similarly, before Standard Containers, by the time a software component ran in production, it had been individually built, configured, bundled, documented, patched, vendored, templated, tweaked and instrumented by 10 different people on 10 different computers.
+Builds failed, libraries conflicted, mirrors crashed, post-it notes were lost, logs were misplaced, cluster updates were half-broken.
+The process was slow, inefficient and cost a fortune - and was entirely different depending on the language and infrastructure provider.
+
+## 5. Industrial-grade delivery
+
+There are 17 million shipping containers in existence, packed with every physical good imaginable.
+Every single one of them can be loaded onto the same boats, by the same cranes, in the same facilities, and sent anywhere in the World with incredible efficiency.
+It is embarrassing to think that a 30 ton shipment of coffee can safely travel half-way across the World in *less time* than it takes a software team to deliver its code from one datacenter to another sitting 10 miles away.
+
+With Standard Containers we can put an end to that embarrassment, by making INDUSTRIAL-GRADE DELIVERY of software a reality.

runtime-config-linux.md

@@ -1,3 +1,5 @@
+# Linux-specific Runtime Configuration
+
 ## Namespaces
 
 A namespace wraps a global system resource in an abstraction that makes it appear to the processes within the namespace that they have their own isolated instance of the global resource.

runtime-config.md

@@ -1,3 +1,59 @@
+# Runtime Configuration
+
+## Hooks
+
+Lifecycle hooks allow custom events for different points in a container's runtime.
+Presently there are `Prestart` and `Poststop`.
+
+* [`Prestart`](#pre-start) is a list of hooks to be run before the container process is executed
+* [`Poststop`](#post-stop)is a list of hooks to be run after the container process exits
+
+Hooks allow one to run code before/after various lifecycle events of the container.
+Hooks MUST be called in the listed order.
+The state of the container is passed to the hooks over stdin, so the hooks could get the information they need to do their work.
+
+Hook paths are absolute and are executed from the host's filesystem.
+
+### Pre-start
+
+The pre-start hooks are called after the container process is spawned, but before the user supplied command is executed.
+They are called after the container namespaces are created on Linux, so they provide an opportunity to customize the container.
+In Linux, for e.g., the network namespace could be configured in this hook.
+
+If a hook returns a non-zero exit code, then an error including the exit code and the stderr is returned to the caller and the container is torn down.
+
+### Post-stop
+
+The post-stop hooks are called after the container process is stopped.
+Cleanup or debugging could be performed in such a hook.
+If a hook returns a non-zero exit code, then an error is logged and the remaining hooks are executed.
+
+*Example*
+
+```json
+    "hooks" : {
+        "prestart": [
+            {
+                "path": "/usr/bin/fix-mounts",
+                "args": ["arg1", "arg2"],
+                "env":  [ "key1=value1"]
+            },
+            {
+                "path": "/usr/bin/setup-network"
+            }
+        ],
+        "poststop": [
+            {
+                "path": "/usr/sbin/cleanup.sh",
+                "args": ["-f"]
+            }
+        ]
+    }
+```
+
+`path` is required for a hook.
+`args` and `env` are optional.
+
 ## Mount Configuration
 
 Additional filesystems can be declared as "mounts", specified in the *mounts* object.

runtime-linux.md

@@ -1,3 +1,5 @@
+# Linux Runtime
+
 ## File descriptors
 By default, only the `stdin`, `stdout` and `stderr` file descriptors are kept open for the application by the runtime.
 

runtime.md

@@ -49,48 +49,4 @@ This event needs to be captured by runc to run onstop event handlers.
 
 ## Hooks
 
-Hooks allow one to run code before/after various lifecycle events of the container.
-Hooks MUST be called in the listed order.
-The state of the container is passed to the hooks over stdin, so the hooks could get the information they need to do their work.
-
-Hook paths are absolute and are executed from the host's filesystem.
-
-### Pre-start
-
-The pre-start hooks are called after the container process is spawned, but before the user supplied command is executed.
-They are called after the container namespaces are created on Linux, so they provide an opportunity to customize the container.
-In Linux, for e.g., the network namespace could be configured in this hook.
-
-If a hook returns a non-zero exit code, then an error including the exit code and the stderr is returned to the caller and the container is torn down.
-
-### Post-stop
-
-The post-stop hooks are called after the container process is stopped.
-Cleanup or debugging could be performed in such a hook.
-If a hook returns a non-zero exit code, then an error is logged and the remaining hooks are executed.
-
-*Example*
-
-```json
-    "hooks" : {
-        "prestart": [
-            {
-                "path": "/usr/bin/fix-mounts",
-                "args": ["arg1", "arg2"],
-                "env":  [ "key1=value1"]
-            },
-            {
-                "path": "/usr/bin/setup-network"
-            }
-        ],
-        "poststop": [
-            {
-                "path": "/usr/sbin/cleanup.sh",
-                "args": ["-f"]
-            }
-        ]
-    }
-```
-
-`path` is required for a hook.
-`args` and `env` are optional.
+See [runtime configuration for hooks](./runtime-config.md)