Added back ECH plan for production page (#1484)

Added back ECH plan for production page as it's important to have. 

## Background & Motivation

Internal GH ticket:
elastic/support-tech-lead#1576

**TL;DR:** This is part of the internal ticket work. In this doc PR, we
add the original elastic cloud plan for production page -
https://web.archive.org/web/20250404052823/https://www.elastic.co/guide/en/cloud/current/ec-planning.html
back to docs v3.

**Details:**
- We need to add some contents to
https://www.elastic.co/docs/troubleshoot/monitoring/node-moves-outages
based on this external KB:
https://support.elastic.dev/knowledge/view/028f4337
- But one crucial page
https://web.archive.org/web/20250404052823/https://www.elastic.co/guide/en/cloud/current/ec-planning.html
was gone from current docs v3 system.
- We understand this page is rephrased and replaced by
https://www.elastic.co/docs/deploy-manage/production-guidance/availability-and-resilience/resilience-in-ech,
however, a) it's not obvious and b) the page redirect is not very
meaningful, it redirects the original page to "elasticsearch production"
page, but we want to go to "elastic cloud hosted production" page, and
c) elastic cloud hosted production page is good to have one independent
page as it makes things easier to update and include important info
pieces that users should know.

## After PR is merged

### a) ECH plan for production page will be back

<img width="1174" alt="image"
src="https://github.com/user-attachments/assets/d478697b-cb43-4736-8c7b-c4602b393c87"
/>
<img width="1197" alt="image"
src="https://github.com/user-attachments/assets/0e0e3473-56b9-418a-afab-276208dbf298"
/>
<img width="1179" alt="image"
src="https://github.com/user-attachments/assets/1f42fcae-0176-4440-ba16-7f1c02f06050"
/>

### b) The page will be referenced in below 2 places:


![image](https://github.com/user-attachments/assets/f5676cad-9938-45dd-be53-75b7e6feef89)

![image](https://github.com/user-attachments/assets/6ab5b61e-7423-4ca8-9287-bd343a80ab41)

### c) The mapped page will change

The mapped page for
https://www.elastic.co/guide/en/cloud/current/ec-planning.html will be
changed from
https://www.elastic.co/docs/deploy-manage/production-guidance/elasticsearch-in-production-environments
(because the current map is not very meaningful) to
https://www.elastic.co/docs/deploy-manage/deploy/elastic-cloud/elastic-cloud-hosted-planning
(available after PR merge).

### d) Some minor change

- Structure change in toc.yml
- Removed some redundant content in
https://www.elastic.co/docs/deploy-manage/production-guidance/availability-and-resilience/resilience-in-ech
since major part will be described in the new page

## Additional Notes

If we decide not to use the structure I proposed above, please help us
at least make the elastic cloud plan for production page a separate page
and make it searchable from internet. It's crucial for us (support) to
guide customer the proper context. (The deletion of this page actually
should not have happened actually but we understand it's during docs
migration so it's fine this time.)

---

Thanks!

---------

Co-authored-by: Edu González de la Herrán <[email protected]>

Author: kunisen

deploy-manage/deploy/elastic-cloud/elastic-cloud-hosted-planning.md

@@ -0,0 +1,68 @@
+---
+mapped_pages:
+  - https://www.elastic.co/guide/en/cloud/current/ec-planning.html
+applies_to:
+  deployment:
+    ess: ga
+products:
+  - id: cloud-hosted
+---
+
+# Plan for production
+
+{{ecloud}} Hosted supports a wide range of configurations. With such flexibility comes great freedom, but also the first rule of deployment planning: Your deployment needs to be matched to the workloads that you plan to run on your {{es}} clusters and {{kib}} instances. Specifically, this means two things:
+* [Does your data need to be highly available?](elastic-cloud-hosted-planning.md#ec-ha)
+* [Do you know when to scale?](elastic-cloud-hosted-planning.md#ec-workloads)
+
+## Does your data need to be highly available? [ec-ha]
+
+With {{ecloud}}, your deployment can be spread across as many as three separate availability zones, each hosted in its own, separate data center. Why this matters:
+
+ * Data centers can have issues with availability. Internet outages, earthquakes, floods, or other events could affect the availability of a single data center. With a single availability zone, you have a single point of failure that can bring down your deployment.
+ * Multiple availability zones help your deployment remain available. This includes your {{es}} cluster, provided that your cluster is sized so that it can sustain your workload on the remaining data centers and that your indices are configured to have at least one replica.
+ * Multiple availability zones enable you to perform changes to resize your deployment with zero downtime.
+
+We recommend that you use at least two availability zones for production and three for mission-critical systems. Just one zone might be sufficient, if your {{es}} cluster is mainly used for testing or development and downtime is acceptable, but should never be used for production.
+
+:::{admonition} Make sure a single zone can serve your whole workload
+Increasing the number of zones should not be used to add more resources. The concept of zones is meant for High Availability (2 zones) and Fault Tolerance (3 zones), but neither will work if the cluster relies on the resources from those zones to be operational.
+:::
+
+With multiple {{es}} nodes in multiple availability zones you have the recommended hardware. The next step is to ensure proper index replication. Each index, with the exception of searchable snapshot indices, should have one or more replicas. Use the [index settings API](https://www.elastic.co/docs/api/doc/elasticsearch/v8/operation/operation-indices-get-settings-1) to find any indices without replicas:
+
+```sh
+GET _all/_settings/index.number_of_replicas
+```
+
+Moreover, a high availability (HA) cluster requires at least three master-eligible nodes. For clusters that have fewer than six {{es}} nodes, any data node in the hot tier will also be a master-eligible node. You can achieve this by having hot nodes (serving as both data and master-eligible nodes) in three availability zones, or by having data nodes in two zones and a tiebreaker (will be automatically added if you choose two zones). For clusters that have six {{es}} nodes and beyond, dedicated master-eligible nodes are introduced. When your cluster grows, consider separating dedicated master-eligible nodes from dedicated data nodes. We recommend using at least 4GB RAM for dedicated master nodes.
+
+The data in your {{es}} clusters is also backed up every 30 minutes, 4 hours, or 24 hours, depending on which snapshot interval you choose. These regular intervals provide an extra level of redundancy. We do support [snapshot and restore](/deploy-manage/tools/snapshot-and-restore.md), regardless of whether you use one, two, or three availability zones. However, with only a single availability zone and in the event of an outage, it might take a while for your cluster come back online. Using a single availability zone also leaves your cluster exposed to the risk of data loss, if the backups you need are not useable (failed or partial snapshots missing the indices to restore) or no longer available by the time that you realize that you might need the data (snapshots have a retention policy).
+
+::::{warning}
+Clusters that use only one availability zone are not highly
+available and are at risk of data loss. To safeguard against data loss,
+you must use at least two availability zones.
+::::
+
+
+::::{warning}
+Indices with no replica, except for searchable snapshot indices,
+are not highly available. You should use replicas to mitigate against
+possible data loss.
+::::
+
+
+::::{warning}
+Clusters that only have one master node are not highly available and are at risk of data loss. You must have three master-eligible nodes.
+::::
+
+## Do you know when to scale? [ec-workloads]
+
+Knowing how to scale your deployment is critical, especially when unexpected workloads hits. Don't forget to [check your performance metrics](../../monitor/access-performance-metrics-on-elastic-cloud.md) to make sure your deployments are healthy and can cope with your workloads.
+
+Scaling with {{ecloud}} is easy: 
+
+* Turn on [deployment autoscaling](/deploy-manage/autoscaling/autoscaling-in-ece-and-ech.md) to let {{ecloud}} manage your deployments by adjusting their available resources automatically.
+* Or, if you prefer manual control, log in to the [{{ecloud}} Console](https://cloud.elastic.co?page=docs&placement=docs-body), select your deployment, select *Edit*, and either increase the number of zones or the size per zone.
+
+The recommendation is to scale up the resources within a single zone until the cluster can take the full load (add some buffer to be prepared for a peak of requests), then scale out by adding additional zones depending on your requirements: two zones for High Availability, three zones for Fault Tolerance. 

deploy-manage/production-guidance/availability-and-resilience/resilience-in-ech.md

@@ -31,31 +31,7 @@ ECH and ECE orchestators automatically handle several aspects of cluster resilie
 * Creating [automatic snapshots](/deploy-manage/tools/snapshot-and-restore.md) at regular configurable intervals, to provide an extra level of redundancy.
 ::::
 
-## Recommendations [ec-ha]
-
-We recommend that you use at least two availability zones for production and three for mission-critical systems. Just one zone might be sufficient, if your {{es}} cluster is mainly used for testing or development and downtime is acceptable, but should never be used for production.
-
-Additionally, using a single availability zone leaves your cluster vulnerable to data loss if backups are unavailable, whether due to failed or incomplete snapshots, missing indices, or expired retention policies that remove the data before it’s needed.
-
-With multiple {{es}} nodes in multiple availability zones you have the recommended hardware, the next thing to consider is the number of replicas for each index. Each index, with the exception of searchable snapshot indexes, should have one or more replicas. Use the [index settings API](https://www.elastic.co/docs/api/doc/elasticsearch/v8/operation/operation-indices-get-settings-1) to find any indices with no replica:
-
-```sh
-GET _all/_settings/index.number_of_replicas
-```
-
-A high availability (HA) cluster requires at least three master-eligible nodes. For clusters that have fewer than six {{es}} nodes, any data node in the hot tier will also be a master-eligible node. You can achieve this by having hot nodes (serving as both data and master-eligible nodes) in three availability zones, or by having data nodes in two zones and a tiebreaker.
-
-For clusters that have six {{es}} nodes and beyond, dedicated master-eligible nodes are introduced. When your cluster grows, consider separating dedicated master-eligible nodes from dedicated data nodes. We recommend using at least 4GB of RAM for dedicated master nodes.
-
-::::{note}
-In {{ece}}, you can customize the threshold at which dedicated master-eligible nodes are introduced by modifying the [deployment templates](/deploy-manage/deploy/cloud-enterprise/deployment-templates.md).
-::::
-
-## Summary
-
-* Clusters that use only one availability zone are not highly available and are at risk of data loss. To safeguard against data loss, you must use at least two availability zones.
-* Indices with no replica, except for searchable snapshot indices, are not highly available. You should use replicas to mitigate against possible data loss.
-* Clusters that only have one master node are not highly available and are at risk of data loss. You must have three master-eligible nodes.
-
-
+## Recommendations [cloud-ha]
 
+* For ECH, review [plan for production](/deploy-manage/deploy/elastic-cloud/elastic-cloud-hosted-planning.md) page for how to plan your deployment for production.
+* For ECE, review [high availability in ECE](/deploy-manage/deploy/cloud-enterprise/ece-ha.md) page for how to configure your ECE installation to be highly available. 

deploy-manage/production-guidance/elasticsearch-in-production-environments.md

@@ -2,7 +2,6 @@
 navigation_title: Run {{es}} in production
 mapped_pages:
   - https://www.elastic.co/guide/en/elasticsearch/reference/current/scalability.html
-  - https://www.elastic.co/guide/en/cloud/current/ec-planning.html
   - https://www.elastic.co/guide/en/cloud-heroku/current/ech-planning.html
 applies_to:
   deployment:
@@ -37,7 +36,7 @@ Your responsibilities when running {{es}} in production depend on the [deploymen
 
 * **Self-managed {{es}}**: You are responsible for setting up and managing nodes, clusters, shards, and replicas. This includes managing the underlying infrastructure, scaling, and ensuring high availability through failover and backup strategies.
 
-* **{{ech}}**: Elastic can [autoscale](../autoscaling.md) resources in response to workload changes. You can choose from different hardware profiles and deployment architectures to apply sensible defaults for your use case. A good understanding of nodes, shards, and replicas is important, as you are still responsible for managing your data and ensuring cluster performance.
+* **{{ech}}**: Elastic can [autoscale](../autoscaling.md) resources in response to workload changes. You can choose from different hardware profiles and deployment architectures to apply sensible defaults for your use case. A good understanding of nodes, shards, and replicas is important, as you are still responsible for managing your data and ensuring cluster performance. Also review the [plan for production](../../deploy-manage/deploy/elastic-cloud/elastic-cloud-hosted-planning.md) for how to plan your deployment for production.
 
 * **{{ece}}**: Similar to {{ech}}, ECE manages {{es}} deployments and automates cluster operations, including scaling and orchestration. However, you are responsible for maintaining the platform itself, including the ECE hosts, operating system updates, and software upgrades. At the deployment level, you must also manage data, monitor performance, and handle shard strategies and capacity planning.
 

deploy-manage/toc.yml

@@ -39,6 +39,7 @@ toc:
                 children:
                   - file: deploy/elastic-cloud/available-stack-versions.md
               - file: deploy/elastic-cloud/access-kibana.md
+              - file: deploy/elastic-cloud/elastic-cloud-hosted-planning.md
               - file: deploy/elastic-cloud/manage-deployments.md
                 children:
                   - file: deploy/elastic-cloud/configure.md