Google Cloud Platform, Cassandra and Mesos

Useful gcloud, gsutil command lines from the Google Cloud Platform (GCP) SDK to get started immediately. When you sign up right now for the Google Cloud Platform, you might get a 300 USD credit to be used within the next 2 montns to play with.

Before starting with the shell and later maybe also API examples, you have to create a project. The easiest is to do that is in the developer console. A project is like a workspace, where all used resources are billed. So for different clients or your different projects, particularly if they are going to be paid from different sources, you might want to have separate GCP projects. Alternatively if particularly API orchestration, would suffer under a strong resource separation, then well, you better have more stuff within one GCP project. To get started one GCP project is enough anyway.

So after you’ve created the project in the Google developer console you’d need to enable the different Google Cloud APIs for your project, so you can manage resources from outside the web console.

Keep the console open as a reference to see how you manipulate GCP objects and instances via command line and API.

# install google cloud sdk
$> curl https://sdk.cloud.google.com | bash

# list authenticated accounts, will likely ask you to login
$> gcloud auth list

# will send you to web site to verify credentials and retrieve security token
$> gcloud auth login

# list config items, important to see you can set default compute region/zone, and project
$> gcloud config list --all

[app]
admin_host (unset)
api_host (unset)
host (unset)
hosted_registry (unset)
[component_manager]
additional_repositories (unset)
disable_update_check (unset)
fixed_sdk_version (unset)
[compute]
region (unset)
zone (unset)
[container]
cluster (unset)
[core]
account = allixender@googlemail.com
credentialed_hosted_repo_domains (unset)
disable_color (unset)
disable_prompts (unset)
disable_usage_reporting = False
project = groundwater-cloud
user_output_enabled (unset)
verbosity (unset)

$> gcloud compute instances --help
$> gcloud compute instances list

# with and without project because default project from config
$> gcloud compute instances describe --project cloud-project1 --zone us-central1-f cloud-instance1
$> gcloud compute instances describe --zone us-central1-f sparkcas1
  
$> gcloud compute instances start --zone us-central1-f sparkcas1

$> gcloud compute instances describe --zone us-central1-f sparkcas1
$> gcloud compute instances list

$> gcloud compute --project "cloud-project1" copy-files myfile.bin user1@cloud-instance1:~ --zone "us-central1-f"

$> gcloud compute --project "cloud-project1" ssh --zone "us-central1-f" "cloud-instance1"

# given that service account was created and the json file contains the key export from creation
# on GCE instances it's better to use service accounts which authenticate the instance to access other resources like 
# cloud storage buckets
$> gcloud auth activate-service-account  --key-file cloud-project1.json

# then you can easily access those buckets from the instance
$> gsutil cp gs://big-geodata1/tasmax_day_CCSM4_rcp60_r1i1p1_20060101-20401231.nc .

# or rsync like with parallel threads
$> gsutil -m rsync -r _site/ gs://www.maerchenland-rostock.de/

Create full base instance commandline

$> gcloud compute --project "groundwater-cloud" instances create "mesos1" --description "Mesos Master and Zookeeper" 
--zone "us-central1-f" --machine-type "g1-small" --network "default" 
--metadata "mesos=master" "zookeeper=master" "cassandra=seed" "startup-script=#!/bin/bash\u000asudo apt-get update && apt-get upgrade -y" 
"sshKeys=akmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDjHZb0zPCijcfSez05RcW0PhVSzMRKgqYTCeQX5gMzDxxiYoL6TKBEhoqbBxbWg35rgfjqVtgH8ViyncbYUP+XcxIe72qQakbCM0hwMRq7I/yKt3TOmXMdF2uDoY23slNaJSQA2J+CUzohFHNNymYr2SJTwRsQv/XjzCBWmu6zoaUkFZK4CTVKEiQul0T2MjKDpH/ly2l1c1R5p04m7+X1QauX67ESN2Z7u/srF/7irvGRtklPeZartVtpCQYq7NEK0pLOCTRAMZH1po1Mi+oBJt/VUeywbQY8pyzbJYxbrTRpShCfeSfZdTljth2792hQET356S9fmaBr2HuH517Z akmoch@acer1\u000aakmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDVIIG7ZCeU5SOIgjmFc9W0MmNferqg1wNgzdvuU+fAp/ZN0UY7p/5V+XQQ3jEVESO8BFHJfhmt38Xca8IwP9FLIYHFWnYUajEH941oWYcQ+5idmBRNWvgYwsU7prlMnc5BeZ+AhZLbrz08xEu1FxncipLdWByrHABCunXaXJzrpggAgJ4ey7pQqzlkWyR9oZCUVJkv/sY+Y6hKMPTvP4/QuSQ2/TLad/32+mAZkvpV+MtpldUwAih8AD6Z40DBSy4lMZvwIKmZ+LlSq2YkDH2z8U5KJTsTXudqSP2c0DSVJIHAwbPSyFjk+2aJzPqZUofVRE/Cw4uWeWRPIpkf9NZ3 akmoch@acer1" 
--maintenance-policy "MIGRATE" --scopes "https://www.googleapis.com/auth/userinfo.email" "https://www.googleapis.com/auth/devstorage.read_only" 
"https://www.googleapis.com/auth/logging.write" --tags "http-server" "https-server" "mesos-master" "zk-master" 
--image "https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1404-trusty-v20150316" 
--no-boot-disk-auto-delete --boot-disk-type "pd-standard" --boot-disk-device-name "mesos1"

# newer gcloud command version tells to mention scope and tags as comma separated list
# also be aware if you want to automatically enable cloud storage (bucket) access via project service acount for the instance change 
# the scope to read_write (can only be modified when the instance is either stopped or at creation time IIRC)
$> gcloud compute --project "groundwater-cloud" instances create "mesos-3" --zone "us-central1-f" --machine-type "n1-standard-2" 
--network "default" --maintenance-policy "MIGRATE" 
--scopes https://www.googleapis.com/auth/devstorage.read_write,https://www.googleapis.com/auth/logging.write 
--tags http-server,https-server --disk name=mesos-3,device-name=mesos-3,mode=rw,boot=yes

or REST

POST https://www.googleapis.com/compute/v1/projects/groundwater-cloud/zones/us-central1-f/instances
{
  "name": "mesos1",
  "zone": "https://www.googleapis.com/compute/v1/projects/groundwater-cloud/zones/us-central1-f",
  "machineType": "https://www.googleapis.com/compute/v1/projects/groundwater-cloud/zones/us-central1-f/machineTypes/g1-small",
  "metadata": {
    "items": [
      {
        "key": "mesos",
        "value": "master"
      },
      {
        "key": "zookeeper",
        "value": "master"
      },
      {
        "key": "cassandra",
        "value": "seed"
      },
      {
        "key": "startup-script",
        "value": "#!/bin/bash\nsudo apt-get update && apt-get upgrade -y"
      },
      {
        "key": "sshKeys",
        "value": "akmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDjHZb0zPCijcfSez05RcW0PhVSzMRKgqYTCeQX5gMzDxxiYoL6TKBEhoqbBxbWg35rgfjqVtgH8ViyncbYUP+XcxIe72qQakbCM0hwMRq7I/yKt3TOmXMdF2uDoY23slNaJSQA2J+CUzohFHNNymYr2SJTwRsQv/XjzCBWmu6zoaUkFZK4CTVKEiQul0T2MjKDpH/ly2l1c1R5p04m7+X1QauX67ESN2Z7u/srF/7irvGRtklPeZartVtpCQYq7NEK0pLOCTRAMZH1po1Mi+oBJt/VUeywbQY8pyzbJYxbrTRpShCfeSfZdTljth2792hQET356S9fmaBr2HuH517Z akmoch@acer1\nakmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDVIIG7ZCeU5SOIgjmFc9W0MmNferqg1wNgzdvuU+fAp/ZN0UY7p/5V+XQQ3jEVESO8BFHJfhmt38Xca8IwP9FLIYHFWnYUajEH941oWYcQ+5idmBRNWvgYwsU7prlMnc5BeZ+AhZLbrz08xEu1FxncipLdWByrHABCunXaXJzrpggAgJ4ey7pQqzlkWyR9oZCUVJkv/sY+Y6hKMPTvP4/QuSQ2/TLad/32+mAZkvpV+MtpldUwAih8AD6Z40DBSy4lMZvwIKmZ+LlSq2YkDH2z8U5KJTsTXudqSP2c0DSVJIHAwbPSyFjk+2aJzPqZUofVRE/Cw4uWeWRPIpkf9NZ3 akmoch@acer1"
      }
    ]
  },
  "tags": {
    "items": [
      "http-server",
      "https-server",
      "mesos-master",
      "zk-master"
    ]
  },
  "disks": [
    {
      "type": "PERSISTENT",
      "boot": true,
      "mode": "READ_WRITE",
      "deviceName": "mesos1",
      "autoDelete": false,
      "initializeParams": {
        "sourceImage": "https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1404-trusty-v20150316",
        "diskType": "https://www.googleapis.com/compute/v1/projects/groundwater-cloud/zones/us-central1-f/diskTypes/pd-standard",
        "diskSizeGb": "10"
      }
    }
  ],
  "canIpForward": false,
  "networkInterfaces": [
    {
      "network": "https://www.googleapis.com/compute/v1/projects/groundwater-cloud/global/networks/default",
      "accessConfigs": [
        {
          "name": "External NAT",
          "type": "ONE_TO_ONE_NAT"
        }
      ]
    }
  ],
  "description": "Mesos Master and Zookeeper",
  "scheduling": {
    "preemptible": false,
    "onHostMaintenance": "MIGRATE",
    "automaticRestart": true
  },
  "serviceAccounts": [
    {
      "email": "default",
      "scopes": [
        "https://www.googleapis.com/auth/userinfo.email",
        "https://www.googleapis.com/auth/devstorage.read_only",
        "https://www.googleapis.com/auth/logging.write"
      ]
    }
  ]
}

Little exercise on Zookeeper and Mesos cluster

Just to be prepared to build anything along mesos, zookeeper, cassandra, spark, geotrellis, gdal …

$> sudo apt-get -y install libgdal-java libgdal-dev gdal-bin netcdf-bin libnetcdf-dev openjdk-7-jdk git build-essential autoconf automake 
libtool zlib1g-dev swig ant libstdc++6-4.6-dev libstdc++5 libstdc++-4.8-dev 
libc++-dev ruby-dev make autoconf nodejs nodejs-legacy python-dev python-boto libcurl4-nss-dev libsasl2-dev maven libapr1-dev libsvn-dev nginx

Can be factored out into e.g. Ansible roles or the likes

# Sourcing out the main install packages to central place in the project.
$> gsutil -m cp -e -c apache-cassandra-2.1.2-bin.tar.gz,apache-cassandra-2.1.5-bin.tar.gz,cassandra-mesos-2.1.2-1.tgz,jdk-8u45-linux-x64.gz,jdk-8u45-linux-i586.gz,jdk-7u80-linux-x64.tgz,jdk-7u80-linux-i586.tgz gs://install-swd5ef6/

Now also those install files can be placed in the machine

$> gsutil cp gs://install-swd5ef6/{cassandra-mesos-2.1.2-1.tgz,apache-cassandra-2.1.2-bin.tar.gz,jdk-7u80-linux-x64.tgz,mesos-0.22.1.tar.gz,spark-1.2.2-bin-hadoop2.4.tgz}

Zookeeper basics

$> sudo apt-get -y install zookeeper zookeeper-bin zookeeperd libzookeeper-java

# editing /etc/zookeeper/conf/myId
# setting up aliases for the cluster members in zoo.cfg and hosts (or via DNS, can always be more automatic certainly)
# restart services
# check status
$> echo stat | nc localhost 2181 | grep Mode
Mode: follower

# or leader depends, of course
# extract mesos, spark and cassandra, jdk and create ENV and export PATHs
$> vi .bash_profile
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_80
JRE_HOME=$JAVA_HOMR/jre
PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH

export JAVA_HOME
export JRE_HOME
export PATH

MESOS_HOME=/home/akmoch/mesos-0.22.1
SPARK_HOME=/home/akmoch/spark-1.2.2-bin-hadoop2.4
CASSANDRA_HOME=/home/akmoch/cassandra-mesos-2.1.2-1

export MESOS_HOME
export SPARK_HOME
export CASSANDRA_HOME

Mesos basics

gotta install it for Ubuntu?!

• unzip, cd into and `./bootstrap

• mkdir build, cd build and ../configure
• make

… oh wait, get a binary install from Mesosphere via apt or package

# Setup
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv E56151BF
DISTRO=$(lsb_release -is | tr '[:upper:]' '[:lower:]')
CODENAME=$(lsb_release -cs)

# Add the repository
echo "deb http://repos.mesosphere.io/${DISTRO} ${CODENAME} main" | \
  sudo tee /etc/apt/sources.list.d/mesosphere.list
sudo apt-get -y update
sudo apt-get -y install mesos marathon

On the one test master start the mesos-master and on the slaves starting the mesos-slaves. Through their local zookeeper instance they’ll find the master. For Marathon, just start sudo service marathon start on all nodes, it’ll negotiate through zookeeper and mesos-master

Create image of a base install

$> gcloud compute --project "groundwater-cloud" images create "my-mesos-base-image" --description "ubu 14.04 LTS, updated, zookeeper installed, jdk available, mesos, cassandra and spark packages on disk" --source-disk https://www.googleapis.com/compute/v1/projects/groundwater-cloud/zones/us-central1-f/disks/mesos1

# and fire up 3 instances from that image
$> gcloud compute --project "groundwater-cloud" instances create "mesos-2" --description "Basic Mesos and Zookeeper" --zone "us-central1-f" 
--machine-type "g1-small" --network "default" --metadata "mesos=master,zookeeper=master,cassandra=seed,sshKeys=akmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDjHZb0zPCijcfSez05RcW0PhVSzMRKgqYTCeQX5gMzDxxiYoL6TKBEhoqbBxbWg35rgfjqVtgH8ViyncbYUP+XcxIe72qQakbCM0hwMRq7I/yKt3TOmXMdF2uDoY23slNaJSQA2J+CUzohFHNNymYr2SJTwRsQv/XjzCBWmu6zoaUkFZK4CTVKEiQul0T2MjKDpH/ly2l1c1R5p04m7+X1QauX67ESN2Z7u/srF/7irvGRtklPeZartVtpCQYq7NEK0pLOCTRAMZH1po1Mi+oBJt/VUeywbQY8pyzbJYxbrTRpShCfeSfZdTljth2792hQET356S9fmaBr2HuH517Z akmoch@acer1\u000aakmoch:ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDVIIG7ZCeU5SOIgjmFc9W0MmNferqg1wNgzdvuU+fAp/ZN0UY7p/5V+XQQ3jEVESO8BFHJfhmt38Xca8IwP9FLIYHFWnYUajEH941oWYcQ+5idmBRNWvgYwsU7prlMnc5BeZ+AhZLbrz08xEu1FxncipLdWByrHABCunXaXJzrpggAgJ4ey7pQqzlkWyR9oZCUVJkv/sY+Y6hKMPTvP4/QuSQ2/TLad/32+mAZkvpV+MtpldUwAih8AD6Z40DBSy4lMZvwIKmZ+LlSq2YkDH2z8U5KJTsTXudqSP2c0DSVJIHAwbPSyFjk+2aJzPqZUofVRE/Cw4uWeWRPIpkf9NZ3 akmoch@acer1" 
--maintenance-policy "MIGRATE" --scopes "https://www.googleapis.com/auth/userinfo.email,https://www.googleapis.com/auth/devstorage.read_only,https://www.googleapis.com/auth/logging.write" 
--tags "http-server,https-server,mesos-master,zk-master" --image "https://www.googleapis.com/compute/v1/projects/groundwater-cloud/global/images/my-mesos-base-image" 
--no-boot-disk-auto-delete --boot-disk-type "pd-standard" --boot-disk-device-name "mesos-2-hdd"

TBC …

More automation links for advanced playgrounds

• A full vagrant GCE toolkit worthwile looking at

• An Ansible GCE Gist

• most mesos automation tools are is either mesosphere, loca vagrant and virtualbox or EC2

• Playa Mesos helps you quickly create Apache Mesos test environments. This project relies on VirtualBox, Vagrant, and an Ubuntu box image which has Mesos and Marathon pre-installed.

• vagrant-mesos Spin up your Mesos cluster with Vagrant! (Both Virtualbox and AWS are supported.)

Mesos and Cassandra

Mesosphere folks currently recommend deployment via Marathon and
provide a marathon.json with a job description to deploy Cassandra. Their mesos cassandra framework is supposedly intelligent enough to bootstrap the cassandra cluster which does initially need known and available seed nodes. Subsequently further nodes can be added to the cluster, because the maximum recommended number of seed nodes is only 3.

Ok, almost that simple, the devil is in the details.

Vanilla Cassandra bootstrap cassandra.yaml

This is a vanilla cassandra.yaml config file. Most iportant details here are the listen_address / rpc_address and seed parameters. Also all nodes in the cluster should share the same cluster_name You want to bind the native, transport and rpc ports on a networked interface, not on localhost. And in vanilla cassandra the seed nodes (1 to max 3) need be defined beforehand and caveat - they need to be IP address apparently, not hostnames. However, listen_address and rpc_address I set to the actual resolvable dns hostname, which could alternatively be achieved by setting listen_interface to eth0 for example.

cluster_name: 'Google Cluster'
num_tokens: 256
hinted_handoff_enabled: true
max_hint_window_in_ms: 10800000 # 3 hours
hinted_handoff_throttle_in_kb: 1024
max_hints_delivery_threads: 2
batchlog_replay_throttle_in_kb: 1024
authenticator: AllowAllAuthenticator
authorizer: AllowAllAuthorizer
permissions_validity_in_ms: 2000
partitioner: org.apache.cassandra.dht.Murmur3Partitioner
disk_failure_policy: stop
commit_failure_policy: stop
key_cache_size_in_mb:
key_cache_save_period: 14400
row_cache_size_in_mb: 0
row_cache_save_period: 0
counter_cache_size_in_mb:
counter_cache_save_period: 7200
commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000
commitlog_segment_size_in_mb: 32
seed_provider:
    - class_name: org.apache.cassandra.locator.SimpleSeedProvider
      parameters:
          - seeds: "10.240.1.54"
concurrent_reads: 32
concurrent_writes: 32
concurrent_counter_writes: 32
memtable_allocation_type: heap_buffers
index_summary_capacity_in_mb:
index_summary_resize_interval_in_minutes: 60
trickle_fsync: false
trickle_fsync_interval_in_kb: 10240
storage_port: 7000
ssl_storage_port: 7001
listen_address: mesos-2
start_native_transport: true
native_transport_port: 9042
start_rpc: true
rpc_address: mesos-2
rpc_port: 9160
rpc_keepalive: true
rpc_server_type: sync
thrift_framed_transport_size_in_mb: 15
incremental_backups: false
snapshot_before_compaction: false
auto_snapshot: true
tombstone_warn_threshold: 1000
tombstone_failure_threshold: 100000
column_index_size_in_kb: 64
batch_size_warn_threshold_in_kb: 5
compaction_throughput_mb_per_sec: 16
sstable_preemptive_open_interval_in_mb: 50
read_request_timeout_in_ms: 5000
range_request_timeout_in_ms: 10000
write_request_timeout_in_ms: 2000
counter_write_request_timeout_in_ms: 5000
cas_contention_timeout_in_ms: 1000
truncate_request_timeout_in_ms: 60000
request_timeout_in_ms: 10000
cross_node_timeout: false
endpoint_snitch: SimpleSnitch
dynamic_snitch_update_interval_in_ms: 100
dynamic_snitch_reset_interval_in_ms: 600000
dynamic_snitch_badness_threshold: 0.1
request_scheduler: org.apache.cassandra.scheduler.NoScheduler
server_encryption_options:
    internode_encryption: none
    keystore: conf/.keystore
    keystore_password: cassandra
    truststore: conf/.truststore
    truststore_password: cassandra
client_encryption_options:
    enabled: false
    keystore: conf/.keystore
    keystore_password: cassandra
internode_compression: all
inter_dc_tcp_nodelay: false

Alternatively as explained, to not need to setting different hostname in each node’s yaml

listen_address:
listen_interface: eth0
rpc_address:
rpc_interface: eth0

And, maybe to be clear, of course each cassandra installation (maybe already included in a base image) should be existing and
identical.

For comparison, the mesos-cassandra pre-packaged cassandra.yaml config file. Most obvious, the path names and seed nodes placeholders. Also for some reason rpc_addressis set to localhost and listen_address is left free, which should result in either getting the right address viahostname or localhost. Initially this combination is ok on single node test, but in multinode cluster all nodes should be able to talk to each other (gossip) and from Spark whatever via application ports 9042.

The mesos-cassandra package does in fact not need to be pre-installed. Rather the package with customised mesos.yaml and cassandra.yaml should reside somewhere web/network accessible, so the mesos scheduler can pull and deploy it on the nodes it will designate.

Problematic or deceiving is the initially provided mesos.yaml and cassandra.yaml config:

# mesos.yaml
mesos.executor.uri: 'http://downloads.mesosphere.io/cassandra/cassandra-mesos-2.1.2-1.tgz'
mesos.master.url: 'zk://localhost:2181/mesos'
state.zk: 'localhost:2181'
java.library.path: '/usr/local/lib/libmesos.so'
cassandra.noOfHwNodes: 1
cassandra.minNoOfSeedNodes: 1
resource.cpus: 1.0
resource.mem: 2048
resource.disk: 2000

# cassandra.yaml
cluster_name: 'MesosCluster'
num_tokens: 256
hinted_handoff_enabled: true
max_hint_window_in_ms: 10800000 # 3 hours
hinted_handoff_throttle_in_kb: 1024
max_hints_delivery_threads: 2
batchlog_replay_throttle_in_kb: 1024
authenticator: AllowAllAuthenticator
authorizer: AllowAllAuthorizer
permissions_validity_in_ms: 2000
partitioner: org.apache.cassandra.dht.Murmur3Partitioner
data_file_directories:
    - /tmp/cassandra/${clusterName}/data
commitlog_directory: /tmp/cassandra/${clusterName}/commitlog
disk_failure_policy: stop
commit_failure_policy: stop
key_cache_size_in_mb:
key_cache_save_period: 14400
row_cache_size_in_mb: 0
row_cache_save_period: 0
counter_cache_size_in_mb:
counter_cache_save_period: 7200
saved_caches_directory: /tmp/cassandra/${clusterName}/saved_caches
commitlog_sync: periodic
commitlog_sync_period_in_ms: 10000
commitlog_segment_size_in_mb: 32
seed_provider:
    - class_name: org.apache.cassandra.locator.SimpleSeedProvider
      parameters:
          - seeds: "${seedNodes}"
concurrent_reads: 32
concurrent_writes: 32
concurrent_counter_writes: 32
memtable_allocation_type: heap_buffers
index_summary_capacity_in_mb:
index_summary_resize_interval_in_minutes: 60
trickle_fsync: false
trickle_fsync_interval_in_kb: 10240
storage_port: 7000
ssl_storage_port: 7001
listen_address:
start_native_transport: true
native_transport_port: 9042
start_rpc: true
rpc_address: localhost
rpc_port: 9160
rpc_keepalive: true
rpc_server_type: sync
thrift_framed_transport_size_in_mb: 15
incremental_backups: false
snapshot_before_compaction: false
auto_snapshot: true
tombstone_warn_threshold: 1000
tombstone_failure_threshold: 100000
column_index_size_in_kb: 64
batch_size_warn_threshold_in_kb: 5
compaction_throughput_mb_per_sec: 16
sstable_preemptive_open_interval_in_mb: 50
read_request_timeout_in_ms: 5000
range_request_timeout_in_ms: 10000
write_request_timeout_in_ms: 2000
counter_write_request_timeout_in_ms: 5000
cas_contention_timeout_in_ms: 1000
truncate_request_timeout_in_ms: 60000
request_timeout_in_ms: 10000
cross_node_timeout: false
endpoint_snitch: SimpleSnitch
dynamic_snitch_update_interval_in_ms: 100
dynamic_snitch_reset_interval_in_ms: 600000
dynamic_snitch_badness_threshold: 0.1
request_scheduler: org.apache.cassandra.scheduler.NoScheduler
server_encryption_options:
    internode_encryption: none
    keystore: conf/.keystore
    keystore_password: cassandra
    truststore: conf/.truststore
    truststore_password: cassandra
client_encryption_options:
    enabled: false
    keystore: conf/.keystore
    keystore_password: cassandra
internode_compression: all
inter_dc_tcp_nodelay: false

The mesos.yaml provides zookeeper endpoint to find the mesos-master as well as a few scaling parameters … AND the package that will be deployed on the nodes in the cluster. This package then again contains the provided cassandra.yaml config that needs to be fitted for our deployment!

Reconciling so far. Updating the cassandra.yaml and mesos.yaml to reflect our deployment, including the designated URL from where to pull
our customised package, uploading the now configured cassandra-mesos folder to that location, and then one can initiate the framework via bin/cassandra-mesos (just like bin/cassandra).

So far so good. That deploys and starts a cassandra cluster with multiple instances throughout our mesos cluster and you don’t have to think about seed nodes yourself, all bootstrapping included. You still need the cassandra nodetool and cqlsh commands handy from your “work directory” if you want to have a look into the cluster yourself.

The deployment happens with the predefined size, BUT there are no handy means to add more nodes/instances via standard mesos techniques (TBC?).

Here is where Mesos Marathon comes into play again. Marathon basically handles deployments as long running apps and keeps a handle on them so you can scale them up and down through their lifetime. Also Maraton provides a REST api where you POST your app definition as described by Mesosphere…

Mesosphere folks currently recommend deployment via Marathon and
provide a marathon.json with a job description to deploy Cassandra.

Different Mesos Cassandra examples

So here the literature gets a bit blurry. And in fact all the examples are easier to reproduce for single nodes. In multiple nodes I just can’t seem to get it deployed properly …

There is this latest approach via Marathon, where an exectutor and framework jarfile are deployed together with a vanilla cassandra package. But there often tend to be resource conflicts. So I tried with biger and bigger machines, a GCE n1-standard-2 with 2 vCPU and 3,7 GB RAM.

And most important for the deploy JSON description:

"id": "marathon-cas12",
"instances": 1,
"cpus": 0.5,
"mem": 512,
"ports": [
 0
],

The upper part seems to provide resources to deploy cassandra, not to run cassandra .. but then for the rescaling in Marathon it doesn’t quite seem to make sense! Therefore be generous where cassandra’s resources are declared, cassandra will eventually at least claim 1 - 1.2 CPU units and 2GB+ RAM.

And if you use that Marathon.json you have to you the provided jre too,, the framework apparently relies on that.

Conclusion so far

I find the current state of Cassandra-on-Mesos difficult to reproduce in production. The scaling is not quite easy to follow up on, and how reliable it is or so…

And thinking of resource hungry cassandra database, you might just add the vanilla install with a template configuration to a base image or the likes, and when bootstrapping the cluster set one or two seed nodes known from your cloud environment. The bootstrap and seed node specialty only happens once a lifetime of the database cluster. If if that seed node goes down later, scaling up by calling out different seed node (just some that are alive basically) will do to dynamically add nodes to the cluster.