Provisioned Machine Requirements

The requirements for how a provisioned machine should behave will depend on the entites subsequently deployed there.

Below are a set of common assumptions, made by many entity implementations, which could cause subsequent errors if they do not hold. These relate to the machine's configuration, rather than additional networking or security that a given Cloud might offer.

Also see the Troubleshooting docs.

Remote Access

SSH or WinRM Access

Many entities require ssh'ing (or using WinRM for Windows), to install and configure the software.

An example of disabling all ssh'ing is shown below:

location:
  aws-ec2:us-east-1:
    identity: XXXXXXXX
    credential: XXXXXXXX
    waitForSshable: false
    pollForFirstReachableAddress: false
services:
- type: org.apache.brooklyn.entity.software.base.EmptySoftwareProcess
  brooklyn.config:
    onbox.base.dir.skipResolution: true
    sshMonitoring.enabled: false

Parsing SSH stdout: No Extra Lines

For entities that execute ssh commands, these sometimes parse the resulting stdout.

It is strongly recommended that VMs are configured so that no additional stdout is written when executing remote ssh (or WinRM) commands. Such stdout risks interfering with the response parsing in some blueprints.

For example, if configuring the VM to write out "Last login" information, this should be done for only "interactive" shells (see Stackoverflow for more details).

Passwordless Sudo

Does passwordless sudo work?

Try executing:

sudo whoami

See Passwordless Sudo.

Advertised Addresses

Hostname Resolves Locally

Does the hostname known at the box resolve at the box?

Try executing:

ping $(hostname)

if not, consider setting generate.hostname: true in the location config, for jclouds-based locations.

IP Resolves Locally

For the IP address advertised in Brooklyn using the sensor host.addresses.private (or host.subnet.address), can the machine reach that IP?

Get the sensor value, and then try executing:

ping ${PRIVATE_IP}

Is there a public IP (advertised using the sensor host.addresses.public, or host.address), and can the machine reach it?

Get the sensor value, and then try executing:

ping ${PUBLIC_IP}

Networking

Public Internet Access

Can the machine reach the public internet, and does DNS resolve?

Try executing:

ping www.example.org

Machine's Hostname in DNS

Is the machine hostname well-known? If ones does a DNS lookup, e.g. from the Brooklyn server, does it resolve and does it return the expected IP (e.g. the same IP as the host.addresses.public sensor)? Try using the hostname that the machine reports when you execute hostname.

Many blueprints do not require this, instead using IP addresses directly. Some blueprints may include registration with an appropriate DNS server. Some clouds do this automatically.

Reachability

When provisioning two machines, can these two machines reach each other on the expected IP(s) and hostname(s)?

Try using ping from one machine to another using the public or subnet ip or hostname. However, note that ping requires access over ICMP, which may be disabled. Alternatively, try connecting to a specific TCP port using telnet <address> <port>.

Firewalls

What firewall(s) are running on the machine, and are the required ports open? On Linux, check things like iptables, firewalld, ufw or other commercial firewalls. On Windows, check the settings of the Windows Firewall.

Consider using openIptables: true, or even stopIptables: true.

Sufficient Entropy for /dev/random

Is there sufficient entropy on the machine, for /dev/random to respond quickly?

Try executing:

{ cat /dev/random > /tmp/x & } ; sleep 10 ; kill %1 ; { cat /dev/random > /tmp/x & } ; sleep 1 ; kill %1 ; wc /tmp/x | awk '{print $3}'

The result should be more than 1M.

If not, consider setting installDevUrandom: true for jclouds-based locations.

See instructions to Increase Entropy.

File System

Permissions of /tmp

Is /tmp writable?

Try executing:

touch /tmp/amp-test-file ; rm /tmp/amp-test-file

Are files in /tmp executable (e.g. some places it has been mounted NO_EXECUTE)?

Try executing:

echo date > /tmp/brooklyn-test.sh && chmod +x /tmp/brooklyn-test.sh && /tmp/brooklyn-test.sh && rm /tmp/brooklyn-test.sh