Hot Starts Best Practises
Tips and Best practises to properly plan and set the preprovisioned sandboxes pool size
The right Hot Start configuration depends on the type of event you are running. A live workshop with 50 attendees needs a different setup than an always-available embedded lab on your website.
This guide provides recommendations for pool sizing, timing, and cleanup for the most common event types. Use it alongside the Hot Start setup instructions to configure your pools.
Key principle: The goal is to give every participant an almost instant-start experience without overprovisioning sandboxes you'll pay for but no one uses.
Self-paced on-demand training (university, education platform, embedded lab)
These are labs embedded on your website, documentation portal, or learning management system. There is no scheduled event – participants arrive at any time.
Recommended setup
Hot Start type: Always Hot
Pool size: Start with 2–4 hot sandboxes per track. This covers steady trickle traffic. If you see periods of delay (e.g., after a marketing email or course enrollment spike), increase temporarily. Keep in mind that always-hot sandboxes run 24/7 – 2 sandboxes equals approximately 8,760 hot start hours per year per track. Review traffic regularly and scale down if the track sees low or seasonal usage.
Auto-refill: On. The pool replenishes automatically as sandboxes are claimed. With auto-refill on, a small pool handles high throughput – you rarely need more than 4 instances for steady traffic.
When to adjust
If you are running a campaign, newsletter, or course launch that drives a burst of traffic, consider temporarily increasing the pool size or creating an additional scheduled pool to cover the spike. Switch back afterward to avoid ongoing cost.
Cleanup
There is no cleanup event, but review your always-hot pools monthly. Delete pools for tracks that are no longer active or receiving traffic.
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
Live workshop
An instructor-led session with a known start time and a defined group of registered participants. Typical size: 20–200 attendees.
Recommended setup
Hot Start type: Scheduled or Invite-scoped. Use Invite-scoped if you want the pool reserved exclusively for participants who access the track through a specific invite link.
Pool size: 65–70% of registrations. Not everyone who registers will show up. If you have 100 registrations, set your pool to 65–70 sandboxes. Sizing in this range already builds in a small buffer for latecomers, so you do not need auto-refill.
Auto-refill: Off. For live workshops, demand is front-loaded – nearly everyone joins within the first 15–20 minutes. If auto-refill were on and all sandboxes were claimed at the start, the pool would spin up a new batch that nobody needs. Size your pool accurately upfront and leave auto-refill off.
Start provisioning: At least 1 hour before the workshop starts. If your track setup scripts are complex or your pool is large, give yourself more time. Instruqt provisions sandboxes in batches – it starts with around 20 and scales up, so a large pool takes longer to fully ready.
End time: Set the pool end time to 15–30 minutes after the scheduled session start. By that point, everyone who is going to join has joined and claimed a sandbox. Unclaimed sandboxes will be cleaned up automatically when the pool expires.
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
Example
You are running a workshop at 10:00 AM CET for 100 registered participants.
Pool size: 70 sandboxes
Start provisioning: 9:00 AM CET
Pool end time: 10:30 AM CET
Auto-refill: Off
Common mistakes
Setting the pool size equal to registrations. You will overprovision and pay for sandboxes that sit unclaimed. Aim for 65–70%.
Enabling auto-refill. For a live workshop, auto-refill creates waste – everyone joins at the start, not throughout the day. Size the pool accurately instead.
Forgetting to set an end time. Without an end time, the pool runs until you manually delete it.
Provisioning too late. If you have 70 sandboxes with a 5-minute setup script, you need time for all of them to be ready. Test your provisioning time in advance and allow at least 1 hour of lead time.
Webinar
A large-audience event (often 200+ registrations) where a speaker presents and participants optionally access a hands-on lab.
Recommended setup
Hot Start type: Scheduled or Invite-scoped.
Pool size: 20–30% of registrations. Most webinar attendees watch passively. If you have 500 registrations, provision 100–150 sandboxes.
Auto-refill: On. During a webinar, the presenter has no time to monitor and adjust the Hot Start pool. Auto-refill takes care of replacing claimed sandboxes without manual intervention.
Start provisioning: At least 1 hour before the webinar.
End time: 30 minutes after the webinar starts. Participants who are going to try the lab typically do so early in the session.
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
Example
You are hosting a webinar at 5:00 PM CET for 400 registrations.
Pool size: 100 sandboxes
Start provisioning: 4:00 PM CET
Pool end time: 5:30 PM CET
Auto-refill: On
Common mistakes
Treating webinar sizing like workshop sizing. A 400-person webinar does not need 280 sandboxes. Webinar audiences are much less likely to start the hands-on component.
Post-webinar access
If you want to give attendees access to the hands-on lab after the webinar, consider creating a separate always-hot pool as you would for an on-demand event. Use a smaller pool size (2–4 sandboxes) with auto-refill on. This allows you to follow up with everyone on the webinar sign-up list and offer them the lab experience, while keeping the pool size and cost under control.
Multi-day training
A training program that runs over multiple days (e.g., a 3-day certification course). Participants return each day, working through different tracks or modules across morning and afternoon sessions.
Recommended setup
Hot Start type: Scheduled – create one pool per time block, per day.
Pool size: 90–100% of enrolled participants per pool. Multi-day training participants have committed to the program and typically paid for it, so show-up rates are much higher than one-off events.
Auto-refill: Off.
Start provisioning: At least 1 hour before each session.
End time: 30 minutes after each session starts
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
One pool per time block – not one per day If possible, we recommend to group tracks that run at the same time into one pool, and create a separate pool for each time slot in the day. If your training day has a morning session and an afternoon session, create one morning pool and one afternoon pool. This way, afternoon sandboxes only spin up when you actually need them – not from the start of the day.
Do not put all tracks into a single daily pool. If morning and afternoon tracks share one pool, the afternoon sandboxes spin up hours before anyone needs them and you pay for that idle time.
Tip: We recommend building your training content as shorter, modular tracks (around 60–90 minutes each) rather than a single long track. Smaller tracks are both easier to consume for the end user, and easier to maintain for your team. Shorter tracks can be reused for other purposes like demos or workshops, and give you more precise control over provisioning timing.
Example
You are running a 3-day certification training (Mon–Wed) for 40 enrolled participants. Each day has two morning tracks (9:00–10:30 AM and 11:00 AM–12:30 PM) and two afternoon tracks (1:30–3:00 PM and 3:30–5:00 PM). You create two pools per day – one covering the morning tracks, one covering the afternoon tracks.
For each day, the morning pool (covering Track A and Track B) starts provisioning at 8:00 AM and ends at 9:30 AM. The afternoon pool (covering Track C and Track D) starts provisioning at 12:30 PM and ends at 2:00 PM. Both pools are sized at 40 sandboxes with auto-refill off.
Adjusting across days
Track your actual attendance from day to day. If you notice fewer participants showing up on Day 2 or Day 3, reduce the pool size for the remaining days. Since you are creating separate pools per time block, this is straightforward – just set a lower number when you create the next pool.
Common mistakes
Creating one long-running pool for the entire training. You pay for sandboxes sitting idle overnight. Create per-session pools instead.
Grouping all tracks for a day into one pool. If morning and afternoon tracks share a pool, afternoon sandboxes spin up at the start of the day, and stay unclaimed resulting in higher costs. Split the pools by the time block.
Using the same pool size on later days without checking attendance. If you see drop-off after Day 1, reduce pool sizes for subsequent days.
Conference hands-on session
A scheduled breakout or hands-on lab session at a conference. The audience is typically pre-registered for the session slot. High-volume, short-window demand.
Recommended setup
Hot Start type: Scheduled or Invite-scoped.
Pool size: 70–80% of registered seats. Conference session registration tends to be more reliable than webinar registration, but some no-shows are expected. For a 150-seat session, provision 110–120 sandboxes.
Auto-refill: Off in most cases. Size your pool to cover expected attendance upfront. If your session is open to walk-by attendees from the conference floor who were not registered in advance, you may want to enable auto-refill as a buffer – but this is the exception, not the rule.
Start provisioning: At least 1 hour before the session. If you are provisioning 100+ sandboxes, give yourself more time. Instruqt provisions in batches – it starts with around 20 sandboxes and scales up, so large pools take longer to fully ready.
End time: 30–45 minutes after the session starts. Conference sessions tend to have more late arrivals than workshops, so give a slightly longer window before cleaning up unclaimed sandboxes.
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
Example
You have a 90-minute hands-on session at a conference, 2:00 PM CET, 150 registered seats.
Pool size: 115 sandboxes
Start provisioning: 1:00 PM CET
Pool end time: 2:45 PM CET
Auto-refill: Off
Common mistakes
Not starting provisioning early enough. Large pools take time because Instruqt provisions in batches – starting with around 20 and scaling up. For 100+ sandboxes, give yourself at least an hour and test your timing beforehand.
Not testing beforehand. Run a small test pool a day before the conference. Claim a sandbox from the pool and verify that the track launches correctly. This confirms the full flow from provisioning to claiming works as expected.
Conference booth / expo demo
A booth or demo station at a conference expo floor. Visitors walk up and try a short demo. Traffic is unpredictable – it comes in bursts and lulls throughout the expo hours.
Recommended setup
Hot Start type: Scheduled.
Pool size: 2–8 sandboxes per track, based on two factors: (1) how many hands-on stations you have at the booth, and (2) how long a typical demo takes. For a 10-minute demo with 2 stations, 3–4 sandboxes is usually enough – one active per station, plus 1–2 ready to go as visitors rotate through.
Auto-refill: On. Unlike events with a fixed audience, booth traffic is continuous and unpredictable. The pool replenishes on its own as visitors claim and finish sandboxes.
Start provisioning: When the expo floor opens.
End time: When the expo floor closes (or the last day of the conference).
Example
You are running a booth demo across a 2-day conference expo (10:00 AM – 6:00 PM CET each day), with 2 demo stations and a 10-minute demo.
Pool size: 4 sandboxes per track
Auto-refill: On
Start provisioning: 10:00 AM CET Day 1
Pool end time: 6:00 PM CET Day 2
Note: Setting a pool end time only removes unclaimed sandboxes. Participants who have already started a sandbox are not affected - their session depends on Idle TimeOut setting, or continues until the track's time-to-live (TTL) expires.
Common mistakes
Overprovisioning because you expect "conference-scale" traffic. Booth traffic is sequential, not simultaneous. A small pool matched to your station count with auto-refill handles most booth scenarios comfortably.
Not setting an end time. If the expo runs 10 AM – 6 PM, set the pool to end at 6 PM. Otherwise you pay for sandboxes sitting idle overnight.
Single prospect or small group demo
You are sharing a lab with one prospect or a small group at a specific company – typically as part of a sales or pre-sales motion.
One-off demo (single prospect)
Hot Start type: Scheduled.
Pool size: 1 sandbox per track. There is one person (or a small handful) accessing the lab – you do not need more.
Auto-refill: Off. With only one person claiming the sandbox, there is nothing to refill.
Start provisioning: 1 hour before you share the link.
End date: Set an end date. A few days is usually enough for the prospect to complete the lab. Without an end date, the pool runs indefinitely and you pay for a sandbox that may never be claimed.
Recurring demos (multiple prospects throughout the week)
If your sales team regularly sends demos to different prospects, it may be easier to maintain a small always-hot pool rather than creating a new scheduled pool each time.
Hot Start type: Always Hot.
Pool size: 1–2 sandboxes per track.
Auto-refill: On. As one prospect claims a sandbox, the pool refills so the next prospect also gets an instant start.
Review: Check the pool weekly. If demo activity slows down, delete the pool to avoid unnecessary cost.
General tips
Always test before the event. Create a small test pool of 1–2 sandboxes well in advance. Claim a sandbox, confirm the track launches correctly, and check that auto-refill (if enabled) replaces the claimed sandbox. Testing both provisioning and claiming avoids surprises during your event.
⚠️ Set your track's time-to-live (TTL) to match the event duration. If the TTL is shorter than your event, sandboxes will expire while participants are still working. They will lose their progress and have to restart. For live events, set the TTL to at least the full duration of the session.
Understand how provisioning scales. Instruqt does not spin up all sandboxes at once. It provisions in batches, starting with around 20 and scaling up from there. For large pools (100+ sandboxes), make sure you start provisioning at least 1 hour before the event – and test your timing beforehand so you know exactly how long your pool takes to fully ready.
Monitor your pool during the event. Check the Hot Start page to see how many sandboxes have been claimed vs. how many are still available. This gives you data to improve sizing for future events.
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