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DCOS Cluster with 3 masters, Exhibitor/Zookeeper backed by an AWS S3 bucket, and AWS DNS Mesosphere Documentation

Getting Started Installing

Installing Enterprise Edition

Configuration parameters

Here are the DCOS cluster configuration parameters. The DCOS build uses these parameters to create a customized install.

bootstrap_url

This parameter specifies the location for the DCOS installer to store the customized DCOS build files. This location can be local ("bootstrap_url":"file:///tmp/dcos") or hosted

(http://<your-web-server>).

cluster_name

This parameter specifies the name of your cluster. For example, "cluster_name": "zk-example".

dns_search

This parameter specifies a space-separated list of domains that are tried when an unqualified domain is entered (e.g. domain searches that do not contain ‘.’). The Linux implementation of /etc/resolv.conf restricts the

maximum number of domains to 6 and the maximum number of characters the setting can have to 256. For more information, see man /etc/resolv.conf.

A search line with the specified contents is added to the /etc/resolv.conf file of every cluster host.

search can do the same things as domain and is more extensible because multiple domains can be specified.

In this example, example.com has public website www.example.com and all of the hosts in the datacenter have fully qualified domain names that end with dc1.example.com. One of the hosts in your datacenter has the hostname foo.dc1.example.com. If dns_search is set to ‘dc1.example.com example.com’, then every DCOS host which does a name lookup of “foo” will get the A record for foo.dc1.example.com. If a machine looks up www, first www.dc1.example.com would be checked, but it does not exist, so the search would try the next domain, lookup www.example.com, find an A record, and then return it.

"dns_search": "dc1.example.com dc1.example.com example.com dc1.example.com dc2.example.com example.com",

docker_remove_delay

This parameter specifies the amount of time to wait before removing the Docker image generated by the installer. It is recommended that you accept the default value 1 hour.

exhibitor_storage_backend

This parameter specifies the name of Exhibitor storage backend. During DCOS installation, a storage system is required for configuring and orchestrating Zookeeper with Exhibitor on the master nodes. Exhibitor automatically configures your Zookeeper installation on the master nodes during your DCOS installation. The available options are zookeeper, aws_s3, and shared_filesystem:

zookeeper

exhibitor_zk_hosts This parameter specifies a comma-separated list of one or more

Zookeeper node IP addresses to use for configuring the internal Exhibitor instances. Exhibitor uses this Zookeeper cluster to orchestrate it’s configuration.

exhibitor_zk_path This parameter specifies the filepath that Exhibitor uses to store data,

Here is a zookeeper example:

"exhibitor_storage_backend": "zookeeper", "exhibitor_zk_hosts": "10.10.10.1:2181", "exhibitor_zk_path": "/zk-example"

aws_s3

aws_access_key_id This parameter specifies AWS key ID.

aws_region This parameter specifies AWS region for your S3 bucket.

aws_secret_access_key This parameter specifies AWS secret access key.

s3_bucket This parameter specifies name of your S3 bucket.

s3_prefix This parameter specifies S3 prefix to be used within your S3 bucket to be used by

Exhibitor.

Here is an aws_s3 example:

"exhibitor_storage_backend": "aws_s3", "aws_access_key_id": "AKIAIOSFODNN7EXAMPLE", "aws_secret_access_key":

"wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", "aws_region": "us-west-2", "s3_bucket": "mybucket", "s3_prefix": "s3-example"

shared_filesystem

exhibitor_fs_config_dir This parameter specifies the absolute path to the folder that Exhibitor uses

to coordinate its configuration. This should be a directory inside of a Network File System (NFS) mount. For example, if every master has /fserv mounted via NFS, set as

"exhibitor_fs_config_dir": "/fserv/dcos-exhibitor".

Important: With shared_filesystem, all masters must must have the NFS volume mounted and exhibitor_fs_config_dir must be inside of it. If any of your servers are missing the mount, the DCOS cluster will not start.

Here is a shared_filesystem example:

"exhibitor_storage_backend": "shared_filesystem", "exhibitor_fs_config_dir": "/shared-mount"

gc_delay

This parameter specifies th maximum amount of time to wait before cleaning up the executor directories. It is recommended that you accept the default value of 2 days.

master_discovery

This parameter specifies the Mesos master discovery method:

cloud_dynamic For AWS CloudFormation template only: Use an external proxy for the masters that lives at

a static IP, for example, haproxy or nginx. For example,

"master_discovery":"cloud_dynamic".

static Use the Mesos agents to discover the masters by giving each agent a static list of master IPs. The

masters must not change IP addresses, and if a master is replaced, the new master must take the old master’s IP address. For example, "master_discovery":"static".

master_list Specify a JSON-formatted list of your static master IP addresses. This must be specified

in JSON list format. For example, "master_list": "[\"172.17.10.101\", \"172.17.10.102\", \"172.17.10.103\"]".

vrrp Use keepalived with a VIP. You are required to maintain this VIP infrastructure. For example,

"master_discovery":"vrrp".

keepalived_router_id Specify the virtual router ID of the keepalived cluster. You must use the same

virtual router ID across your cluster. For example, "keepalived_router_id":"51".

keepalived_interface Specify the interface that keepalived uses. For example,

"keepalived_interface":"eth1".

keepalived_pass If you’ve set your auth to PASS, specify the same password that you set in your

configuration file. For example, "keepalived_pass":"$MY_STRONG_PASSWORD".

keepalived_virtual_ipaddress Specify the VIP in use by your keepalived cluster. For example,

"keepalived_virtual_ipaddress":"67.34.242.55".

num_masters

This parameter specifies the number of Mesos masters in your DCOS cluster. For example, "num_masters": 3.

resolvers

This required parameters specifies a JSON-formatted list of DNS resolvers for your DCOS host nodes or accept the default value of [\"8.8.8.8\"]. Set this parameter to the most authoritative nameservers that you have. If you want to resolve internal hostnames, set it to a nameserver that can resolve them. If you have no internal hostnames to resolve, it is acceptable to set this to a public nameserver like Google or AWS. For example, "resolvers": "[\"8.8.8.8\", \"8.8.4.4\"]".

*Caution:* If you set the `resolvers` parameter incorrectly, you will permanently damage your configuration and have to reinstall DCOS.

roles

This parameter specifies the Mesos roles to delegate to this node or accept the default value of

"slave_public":

slave_public: Runs the public agent node. This is the default value. For example,

"roles":"slave_public".

master: Runs the master node. For example, "roles":"master".

slave: Runs the private agent node. For example, "roles":"slave". For more information, see Mesos roles.

weights

This parameter specifies the priority of the role or accept the default value of "weights": "slave_public=1". For more information, see Mesos weights.

Example JSON configuration files

DCOS cluster with 3 masters, Exhibitor/Zookeeper backed by another Zookeeper instance, Google DNS

{ "cluster_name": "zk-example", "num_masters": 3, "exhibitor_storage_backend": "zookeeper", "exhibitor_zk_hosts": "10.10.10.1:2181", "exhibitor_zk_path": "/zk-example", "bootstrap_url":"file:///tmp/dcos", "master_discovery":"vrrp", "keepalived_router_id":"51", "keepalived_interface":"eth1", "keepalived_pass":"$MY_STRONG_PASSWORD", "keepalived_virtual_ipaddress":"67.34.242.55", "resolvers": "[\"8.8.8.8\", \"8.8.4.4\"]", "roles": "slave_public", "weights": "slave_public=1" }

DCOS cluster with 3 masters, Exhibitor/Zookeeper backed by a shared filesystem mount, Internal DNS

{ "cluster_name": "fs-example", "num_masters": 3, "exhibitor_storage_backend": "shared_filesystem", "exhibitor_fs_config_dir": "/shared-mount", "bootstrap_url":"file:///tmp/dcos", "resolvers": "[\"10.10.5.1\", \"10.10.6.1\"]", "roles": "slave_public", "weights": "slave_public=1" }

DCOS Cluster with 3 masters, Exhibitor/Zookeeper backed by an AWS S3 bucket, and AWS DNS

"cluster_name": "s3-example", "num_masters": 3, "exhibitor_storage_backend": "aws_s3", "aws_access_key_id": "AKIAIOSFODNN7EXAMPLE", "aws_secret_access_key": "wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", "aws_region": "us-west-2", "s3_bucket": "mybucket", "s3_prefix": "s3-example", "bootstrap_url":"file:///tmp/dcos", "resolvers": "[\"169.254.169.253\"]", "roles": "slave_public", "weights": "slave_public=1" }