Enforce Pre-check Before Deployment

Before deployment, people might need to provide multiple information. For example, which nodes to deploy what services, use which tcp ports to listen on application endpoints, etc.

Even very careful person would make stupid mistakes! e.g, wrong ip format, invalid port, unsupported OS version, machine doesn’t have RAM, etc.

These human errors may not only fail your deployments, but also cause unexpected damages to your existing envs. Even mess up critical envs sometimes. So it’s better we enforce pre-check before update.

One-button click deployment is nice. Lots of DevOps practices drive this trend.

I usually enforce it via Chef + Jenkins:

Core deployment is implemented by Chef
Wrap up it as a jenkins job.

Consequently people only need to trigger the jenkins job with all parameters default.

Here is an example of Jenkins job:

Super easy, isn’t it?

Just one issue. The parameters!

People need to configure server_list and chef_json for correctly. It’s a bit complicated.

Compared to documentation, it’s better we enforce pre-check. Very few people enjoy lengthy manuals. So try your best to help people to avoid common pitfalls and human errors.

Check	Summary
check_ip_format	No invalid ip format
check_ip_list_format	IP list
check_tcp_port_format	Valid TCP port
check_int_format	Valid integers
check_string_not_empty	Parameter is set

Check

Summary

check_ip_format

No invalid ip format

check_ip_list_format

IP list

check_tcp_port_format

Valid TCP port

check_int_format

Valid integers

check_string_not_empty

Parameter is set

Check	Comment
check_capcity_disk	Enough disk capacity
check_capacity_cpu	Enough cpu core
check_capacity_mem	Enough RAM
check_os_version	Supported OS version

Check

Comment

check_capcity_disk

Enough disk capacity

check_capacity_cpu

Enough cpu core

check_capacity_mem

Enough RAM

check_os_version

Supported OS version

Check	Comment
check_ip_reachable	Verify network assumption
check_port_connect	Telnet server port

Check

Comment

check_ip_reachable

Verify network assumption

check_port_connect

Telnet server port

# Import library Chef::Recipe.send(:include, PreCheck::HelperInputFormat) Chef::Recipe.send(:include, PreCheck::HelperInfraCheck) Chef::Recipe.send(:include, PreCheck::HelperNetworkCheck) ################################################################################ # Check input parameters check_nodename_list_format(node['common_basic']['couchbase_hosts']) check_nodename_list_format(node['common_basic']['elasticsearch_hosts']) check_nodename_list_format(node['common_basic']['haproxy_hosts']) check_nodename_format(node['common_basic']['nagios_server'], \ 'nagios_server parameter is invalid') check_tcp_port_format(node['common_basic']['app_https_port'], \ 'app_https_port is not a valid tcp port') check_tcp_port_format(node['common_basic']['haproxy_port'], \ 'haproxy_port is not a valid tcp port') ################################################################################ # Check at infra layer check_hostname(node['hostname']) check_os_version(['ubuntu-14.04'], "#{node['platform']}-#{node['platform_version']}") check_ip_reachable(['www.google.com']) ################################################################################ # Check hardware resource check_capacity_cpu(node['common_basic']['precheck']['all_in_one']['min_cpu_count'], \ node['cpu']['total']) total_memory = node['memory']['total'][0..-3].to_f / (1024 * 1024) check_capacity_cpu(node['common_basic']['precheck']['all_in_one']['min_memory_gb'], \ total_memory)