Cartoon: what is blue-green deployment?

Dolphin's Secret

We all know that dolphins are lovely marine animals . But how many people know , Dolphins can Never sleep .

What kind of ability , So that dolphins can stay awake forever ？ It depends on the special way the dolphin brain works .

Like a man , The dolphin's brain is also divided into two parts: the left brain and the right brain . In the active state of dolphins , Both the left and right brains are awake ：

Of course , Dolphins are also flesh and blood , Also need to rest . While the dolphins are resting , Half of them go to sleep , The other half of the brain is still awake , In order to face all kinds of external situations .

Every two hours , This half sleep and half awake state alternates , For example, this moment left brain sleep, right brain awake , The next moment left brain awake, right brain sleep .

That's the secret that dolphins never really sleep .

What is blue and green deployment ？

Blue and green deployment , English name Blue Green Deployment, It's a way to make sure that the system Continuous service In this case, the deployment mode of going online .

How to ensure the uninterrupted service of the system ？

The blue-green deployment model contains two clusters , It's like the left and right brains of dolphins .

Under normal circumstances without being online , colony A And clusters B The code version of is consistent , And at the same time provide services to the outside world .

When the system is upgraded , Let's start with a cluster （ For example, cluster A） Remove from the load list , Deploy the new version . colony B Still providing services .

When clustering A Upgrade Complete , We re directed load balancing to clusters A, Cluster again B Remove from the load list , Deploy the new version . colony A Re service .

Last , When clustering B And the upgrade is complete , We put clusters B Also back to the load list . This is the time , Both versions of the cluster have been upgraded , And the external service has hardly been interrupted .

What is rolling deployment ？

Rolling deployment , english Rolling update, It is also a way to ensure that the system can Continuous service In this case, the deployment mode of going online .

Unlike blue and green deployment , Rolling deployment is not either or , But in Upgrade the version smoothly with finer granularity .

How to achieve fine-grained smooth upgrade version ？

Rolling deployment requires only one cluster , Different nodes in the cluster can be independently upgraded . Like in one 16 In the cluster of nodes , We choose every upgrade 4 Nodes ：

And so on , In the end, all nodes have been upgraded .

The possibility of immortality

Our bodies , It's like a huge and complex cluster of computers , Each organ is equivalent to a node in the cluster , Organs and organs are connected by innumerable nerves and blood vessels .

For computer clusters , Continuous service is in “ Alive ”. And for humans , Every organ works continuously , Maintain vital signs Is in the “ Alive ”.

Human organs will eventually age , That was the end of human life . If we're before organs age , Replace each organ with a younger one in turn , Whether it's liver or kidney , Muscle or bone , Can this man stay young forever ？

Maybe someone will say , The human brain is also aging , I can't replace the brain too ？ Then I won't be me anymore .

however , The human brain is not independent and indivisible . If we think of the brain as 1000 A collection of even more basic units , Only one thousandth of the brain is replaced at a time , So this person or this person , Maybe even the mind almost never stops .

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