Windows Azure Linux Agent User Guide

Introduction
The Windows Azure Linux Agent (waagent) manages VM interaction with the Windows
Azure Fabric Controller. It provides the following functionality for Linux IaaS
deployments:

* Image Provisioning
  - Creation of a user account.
  - Configuring SSH authentication types.
  - Deployment of SSH public keys and key pairs
  - Setting the host name
  - Publishing the host name to the platform DNS
  - Reporting SSH host key fingerprint to the platform
  - Resource Disk Management
  - Formatting and mounting the resource disk
  - Configuring swap space
* Networking
  - Manages routes to improve compatibility with platform DHCP servers
  - Ensures the stability of the network interface name
* Kernel
  - Configuring virtual NUMA
  - Consume Hyper-V entropy for /dev/random
  - Configuring SCSI timeouts for the root device (which could be remote)
* Diagnostics
  - Console redirection to the serial port

The information flow from the platform to the agent occurs via two channels: 
A TCP endpoint exposing a REST API and a boot-time attached DVD for IaaS 
deployments. The DVD includes an OVF-compliant configuration file that includes
all provisioning information other than the actual SSH keypairs. The deployment
configuration and topology are obtained over the REST API.

Supported Linux Distributions
1.CentOS 6.0+
2.Ubuntu 12.04+
3.Suse (SLES) 11SP2+
4.Open Suse 12.1+

Requirements
Waagent depends on some system packages in order to function properly:
1.Python 2.4+
2.Openssl 1.0+
3.Openssh 5.3+
4.Filesystem utilities: sfdisk, fdisk, mkfs
5.Password tools: chpasswd
6.Text processing tools: sed, grep

Installation
Installation using an RPM or a DEB package is preferred. If installing 
manually,waagent should be copied to /usr/sbin/waagent and installed by 
running: /usr/sbin/waagent -install

Command Line Options
Flags
-verbose: Increase verbosity of specified command
-force: Skip interactive confirmation for some commands
Commands
-help: Lists the supported commands and flags.
-install: Checks the system for required dependencies. 
 Creates the SysV init script (/etc/init.d/waagent), 
 the logrotate configuration file (/etc/logrotate.d/waagent), 
 and configures the image to run the init script on boot. 
 Writes sample configuration file to /etc/waagent.conf. 
 Any existing configuration file is moved to /etc/waagent.conf.old. 
 Detects kernel version and apply VNUMA workaround if necessary. 
 Moves udev rules that may interfere with networking 
 (/lib/udev/rules.d/75-persistent-net-generator.rules,
  /etc/udev/rules.d/70-persistent-net.rules) to /var/lib/waagent/.
-uninstall: Unregisters the init script from the system and deletes it. 
 Deletes the logrotate configuration and the waagent config file in 
 /etc/waagent.conf. 
 Automatic reverting of the VNUMA workaround is not supported – please edit 
 the GRUB configuration files by hand to re-enable NUMA if required. 
 Restores any moved udev rules.
-deprovision: Attempt to clean the system and make it suitable for 
 re-provisioning. Deletes the following:
 1. All SSH host keys 
    (if Provisioning.RegenerateSshHostKeyPair is set in the configuration file)
 2. Nameserver configuration in /etc/resolv.conf
 3. Root password from /etc/shadow 
    (if Provisioning.DeleteRootPassword is set in the configuration file)
 4. Cached DHCP client leases.
 5. Resets host name to localhost.localdomain.
 WARNING! This doesn’t guarantee that the image is cleared of all 
 sensitive information and suitable for redistribution.
-deprovision+user: Everything under deprovision (above) and also deletes 
 the last provisioned user account and associated data.
-version: Displays the version of waagent
-serialconsole: Configures GRUB to mark ttyS0 (the first serial port) as 
 the boot console. This ensures that kernel bootup logs are sent to the 
 serial port and made available for debugging.
-daemon: Run waagent as a daemon to manage interaction with the platform.
 This argument is specified to waagent in the waagent init script.

Configuration
A configuration file (/etc/waagent.conf) controls the actions of waagent. 
A sample configuration file is shown below:

#
# Windows Azure Linux Agent Configuration	
#
Role.StateConsumer=None 
Role.ConfigurationConsumer=None 
Role.TopologyConsumer=None
Provisioning.Enabled=y
Provisioning.DeleteRootPassword=n
Provisioning.RegenerateSshHostKeyPair=y
Provisioning.SshHostKeyPairType=rsa
Provisioning.MonitorHostName=y
ResourceDisk.Format=y
ResourceDisk.Filesystem=ext4
ResourceDisk.MountPoint=/mnt/resource 
ResourceDisk.EnableSwap=n 
ResourceDisk.SwapSizeMB=0
LBProbeResponder=y
Logs.Verbose=n
OS.RootDeviceScsiTimeout=300
OS.OpensslPath=None

The various configuration options are described in detail below. 
Configuration options are of three types : Boolean, String or Integer. 
The Boolean configuration options can be specified as “y” or “n”. 
The special keyword “None” may be used for some string type configuration
entries as detailed below.

Role.StateConsumer: 
Type: String Default: None
If a path to an executable program is specified, the program is invoked at
two events.
1.When the waagent has provisioned the image and the “Ready” state is about
  to be reported to the Fabric. The argument specified to the program 
  will be “Ready”. waagent will not wait for the program to return before 
  continuing.
2.When the waagent has received a shutdown request from the Fabric and is about
  to shutdown the VM. The argument specified to the program will be “Shutdown”.  
  waagent will wait for the program to return before initiating the shutdown 
  process.

Role.ConfigurationConsumer:
Type: String Default: None
If a path to an executable program is specified, 
the program is invoked when the Fabric indicates that a configuration file is 
available for the VM. The path to the XML configuration file is provided as an 
argument to the executable. This may be invoked multiple times whenever the 
configuration file changes. A sample file is provided in the Appendix. Please
note that the XML schema used in this file may change in the future.
The current path of this file is /var/lib/waagent/HostingEnvironmentConfig.xml.

Role.TopologyConsumer: 
Type: String Default: None
If a path to an executable program is specified, 
the program is invoked when the Fabric indicates that a new network topology
layout is available for the VM.The path to the XML configuration file is 
provided as an argument to the executable. This may be invoked multiple times
whenever the network topology changes (due to service healing for example).
A sample file is provided in the Appendix. Please note that the XML schema 
used in this file may change in the future.
The current location of this file is /var/lib/waagent/SharedConfig.xml.

Provisioning.Enabled: 
Type: Boolean Default: y
This allows the user to enable or disable the provisioning functionality in the
agent. Valid values are “y” or “n”. If provisioning is disabled, SSH host and 
user keys in the image are preserved and any configuration specified in the 
Windows Azure provisioning API is ignored.

Provisioning.DeleteRootPassword: 
Type: Boolean Default: n
If set, the root password in the /etc/shadow file is erased during the
provisioning process.

Provisioning.RegenerateSshHostKeyPair: 
Type: Boolean Default: y
If set, all SSH host key pairs (ecdsa, dsa and rsa) are deleted during the
provisioning process from /etc/ssh/. And a single fresh key pair is generated.
The encryption type for the fresh key pair is configurable by the 
Provisioning.SshHostKeyPairType entry. Please note that some distributions will
re-create SSH key pairs for any missing encryption types when the SSH daemon is
restarted (for example, upon a reboot).

Provisioning.SshHostKeyPairType: 
Type: String Default: rsa
This can be set to an encryption algorithm type that is supported by the SSH 
daemon on the VM. The typically supported values are “rsa”, “dsa” and “ecdsa”.
Note that “putty.exe” on Windows does not support “ecdsa”. So, if you intend 
to use putty.exe on Windows to connect to a Linux deployment, please use 
“rsa” or “dsa”.

Provisioning.MonitorHostName: 
Type: Boolean Default: y
If set, waagent will monitor the Linux VM for hostname changes (as returned 
by the “hostname” command) and automatically update the networking 
configuration in the image to reflect the change. In order to push the name
change to the DNS servers, networking will be restarted in the VM. This will
result in brief loss of Internet connectivity.

ResourceDisk.Format: 
Type: Boolean Default: y
If set, the resource disk provided by the platform will be formatted and 
mounted by waagent if the filesystem type requested by the user in 
"ResourceDisk.Filesystem" is anything other than "ntfs". A single partition of
type Linux (83) will be made available on the disk. Note that this partition 
will not be formatted if it can be successfully mounted.

ResourceDisk.Filesystem: 
Type: String Default: ext4
This specifies the filesystem type for the resource disk. Supported values vary
by Linux distribution. If the string is X, then mkfs.X should be present on 
the Linux image.

ResourceDisk.MountPoint: 
Type: String Default: /mnt/resource 
This specifies the path at which the resource disk is mounted.

ResourceDisk.EnableSwap: 
Type: Boolean Default: n 
If set, a swap file (/swapfile) is created on the resource disk and added to
the system swap space.

ResourceDisk.SwapSizeMB:
Type: Integer Default: 0
The size of the swap file in megabytes.

LBProbeResponder: Type: Boolean Default: y
If set, waagent will respond to load balancer probes from the platform 
(if present).

Logs.Verbose: Type: Boolean Default: n
If set, log verbosity is boosted. Waagent logs to /var/log/waagent.log and 
leverages the system logrotate functionality to rotate logs.


OS.RootDeviceScsiTimeout: 
Type: Integer Default: 300
This configures the SCSI timeout in seconds on the root device. If not set, 
the system defaults are used.

OS.OpensslPath:
Type: String Default: None
This can be used to specify an alternate path for the openssl binary to use 
for cryptographic operations.

Appendix
Sample Role Configuration File

<?xml version="1.0" encoding="utf-8"?>
<HostingEnvironmentConfig version="1.0.0.0" goalStateIncarnation="1">
  <StoredCertificates>
    <StoredCertificate name="Stored0Microsoft.WindowsAzure.Plugins.RemoteAccess.PasswordEncryption" certificateId="sha1:C093FA5CD3AAE057CB7C4E04532B2E16E07C26CA" storeName="My" configurationLevel="System" />
  </StoredCertificates>
  <Deployment name="a99549a92e38498f98cf2989330cd2f1" guid="{374ef9a2-de81-4412-ac87-e586fc869923}" incarnation="14">
    <Service name="LinuxDemo1" guid="{00000000-0000-0000-0000-000000000000}" />
    <ServiceInstance name="a99549a92e38498f98cf2989330cd2f1.4" guid="{250ac9df-e14c-4c5b-9cbc-f8a826ced0e7}" />
  </Deployment>
  <Incarnation number="1" instance="LinuxVM_IN_2" guid="{5c87ab8b-2f6a-4758-9f74-37e68c3e957b}" />
  <Role guid="{47a04da2-d0b7-26e2-f039-b1f1ab11337a}" name="LinuxVM" hostingEnvironmentVersion="1" software="" softwareType="ApplicationPackage" entryPoint="" parameters="" settleTimeSeconds="10" />
  <HostingEnvironmentSettings name="full" Runtime="rd_fabric_stable.111026-1712.RuntimePackage_1.0.0.9.zip">
    <CAS mode="full" />
    <PrivilegeLevel mode="max" />
    <AdditionalProperties><CgiHandlers></CgiHandlers></AdditionalProperties></HostingEnvironmentSettings>
    <ApplicationSettings>
      <Setting name="__ModelData" value="&lt;m role=&quot;LinuxVM&quot; xmlns=&quot;urn:azure:m:v1&quot;>&lt;r name=&quot;LinuxVM&quot;>&lt;e name=&quot;HTTP&quot; />&lt;e name=&quot;Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp&quot; />&lt;e name=&quot;Microsoft.WindowsAzure.Plugins.RemoteForwarder.RdpInput&quot; />&lt;e name=&quot;SSH&quot; />&lt;/r>&lt;/m>" />
      <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountEncryptedPassword" value="…" />
      <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountExpiration" value="2015-11-06T23:59:59.0000000-08:00" />
      <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.AccountUsername" value="rdos" />
      <Setting name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Enabled" value="true" />
      <Setting name="Microsoft.WindowsAzure.Plugins.RemoteForwarder.Enabled" value="true" />
      <Setting name="startpage" value="Hello World!" />
      <Setting name="Certificate|Microsoft.WindowsAzure.Plugins.RemoteAccess.PasswordEncryption" value="sha1:C093FA5CD3AAE057CB7C4E04532B2E16E07C26CA" />
    </ApplicationSettings>
    <ResourceReferences>
      <Resource name="DiagnosticStore" type="directory" request="Microsoft.Cis.Fabric.Controller.Descriptions.ServiceDescription.Data.Policy" sticky="true" size="1" path="a99549a92e38498f98cf2989330cd2f1.LinuxVM.DiagnosticStore\" disableQuota="false" />
    </ResourceReferences>
  </HostingEnvironmentConfig>

 
Sample Role Topology File
<?xml version="1.0" encoding="utf-8"?>
<SharedConfig version="1.0.0.0" goalStateIncarnation="2">
  <Deployment name="a99549a92e38498f98cf2989330cd2f1" guid="{374ef9a2-de81-4412-ac87-e586fc869923}" incarnation="14">
    <Service name="LinuxDemo1" guid="{00000000-0000-0000-0000-000000000000}" />
    <ServiceInstance name="a99549a92e38498f98cf2989330cd2f1.4" guid="{250ac9df-e14c-4c5b-9cbc-f8a826ced0e7}" />
  </Deployment>
  <Incarnation number="1" instance="LinuxVM_IN_1" guid="{a7b94774-db5c-4007-8707-0b9e91fd808d}" />
  <Role guid="{47a04da2-d0b7-26e2-f039-b1f1ab11337a}" name="LinuxVM" settleTimeSeconds="10" />
  <LoadBalancerSettings timeoutSeconds="32" waitLoadBalancerProbeCount="8">
    <Probes>
      <Probe name="LinuxVM" />
      <Probe name="03F7F19398C4358108B7ED059966EEBD" />
      <Probe name="47194D0E3AB3FCAD621CAAF698EC82D8" />
    </Probes>
  </LoadBalancerSettings>
  <OutputEndpoints>
    <Endpoint name="LinuxVM:Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" type="SFS">
      <Target instance="LinuxVM_IN_0" endpoint="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" />
      <Target instance="LinuxVM_IN_1" endpoint="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" />
      <Target instance="LinuxVM_IN_2" endpoint="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" />
    </Endpoint>
  </OutputEndpoints>
  <Instances>
    <Instance id="LinuxVM_IN_1" address="10.115.38.202">
      <FaultDomains randomId="1" updateId="1" updateCount="2" />
      <InputEndpoints>
        <Endpoint name="HTTP" address="10.115.38.202:80" protocol="tcp" isPublic="true" loadBalancedPublicAddress="70.37.56.176:80" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="80" to="80" />
          </LocalPorts>
        </Endpoint>
        <Endpoint name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" address="10.115.38.202:3389" protocol="tcp" isPublic="false" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="3389" to="3389" />
          </LocalPorts>
          <RemoteInstances>
            <RemoteInstance instance="LinuxVM_IN_0" />
            <RemoteInstance instance="LinuxVM_IN_2" />
          </RemoteInstances>
        </Endpoint>
        <Endpoint name="Microsoft.WindowsAzure.Plugins.RemoteForwarder.RdpInput" address="10.115.38.202:20000" protocol="tcp" isPublic="true" loadBalancedPublicAddress="70.37.56.176:3389" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="20000" to="20000" />
          </LocalPorts>
        </Endpoint>
        <Endpoint name="SSH" address="10.115.38.202:22" protocol="tcp" isPublic="true" loadBalancedPublicAddress="70.37.56.176:22" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="22" to="22" />
          </LocalPorts>
        </Endpoint>
      </InputEndpoints>
    </Instance>
    <Instance id="LinuxVM_IN_0" address="10.115.58.82">
      <FaultDomains randomId="0" updateId="0" updateCount="2" />
      <InputEndpoints>
        <Endpoint name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" address="10.115.58.82:3389" protocol="tcp" isPublic="false" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="3389" to="3389" />
          </LocalPorts>
        </Endpoint>
      </InputEndpoints>
    </Instance>
    <Instance id="LinuxVM_IN_2" address="10.115.58.148">
      <FaultDomains randomId="0" updateId="2" updateCount="2" />
      <InputEndpoints>
        <Endpoint name="Microsoft.WindowsAzure.Plugins.RemoteAccess.Rdp" address="10.115.58.148:3389" protocol="tcp" isPublic="false" enableDirectServerReturn="false" isDirectAddress="false" disableStealthMode="false">
          <LocalPorts>
            <LocalPortRange from="3389" to="3389" />
          </LocalPorts>
        </Endpoint>
      </InputEndpoints>
    </Instance>
  </Instances>
</SharedConfig>
